opacityn.
/ə(ʊ)ˈpasᵻti/, U.S. /oʊˈpæsədi/ 1.
a. Obscurity of meaning; resistance to interpretation; impenetrability; an instance of this. rare before 20th cent.
ΘΚΠ
the mind > mental capacity > intelligibility > unintelligibility > depth, obscurity > [noun]
deepnessa1000
subtletya1387
difficultyc1405
mistiheadc1425
darknessc1450
obscurity1474
profoundnessc1475
obscureness1509
profundity1559
perplexity1563
opacity1575
darksomeness1583
perplexednessa1586
deptha1593
spinosity1605
abstruseness1628
abstrusity1649
inevidence1673
enigmaticalness1684
dark1699
indistinctness1704
confusion1729
reconditeness1779
obfuscity1832
oracularity1840
irrecognizability1847
recondity1856
unrecognizableness1865
crypticity1892
1575 J. Rolland Treat. Court Venus ii. f. 26 Sa full thair warkis was of opacitie [1884 printed oporcitie] Culd few thairof mak Interpretatioun.
1818 T. L. Peacock Nightmare Abbey i. 16 He plunged into the central opacity of Kantian metaphysics.
1968 Philos. & Phenomenol. Res. 29 189 Obscurity or opacity of meaning.
1991 E. S. Connell Alchymist's Jrnl. (1992) 49 In counting our possession do we not wonder that superior texts teach opacities?
2000 Independent on Sunday 29 Oct. (Review Suppl.) 69/4 A vocabulary of furtive euphemisms whose very opacity testifies to the hideously pervasive fear of the Inquisition.
b. Denseness or obtuseness of intellect or understanding. Also (in quot. 1844): a person exemplifying this. Now rare.
ΘΚΠ
the mind > mental capacity > lack of understanding > stupid, foolish, or inadequate person > person of weak intellect > [noun]
mis-feelinga1382
noddyship?1589
shallow-pate1600
wattle-head1613
insensiblea1618
non-intelligent1628
underhead1643
no conjurer1668
insipid1699
shallow-brains1707
sillytonian1707
inane1710
coof1724
incapable1809
ganache1814
insipidity1822
wanwit1837
opacity1844
stupiditarian1850
scant-brain1864
insensate1877
slowie1901
no-brow1926
1806 J. W. Croker Amazoniad i. ii. 44 Some clerk in a public office, who possesses a comfortable opacity of intellect, and a moderate knowledge of vulgar arithmetic.
1844 T. Carlyle Crit. & Misc. Ess. (1865) IV. 297 The Opacities have been pleased to suppress this election.
1874 L. Carr Judith Gwynne I. iv. 111 A light dawned through the thick opacity of his brain.
1915 C. A. Ellwood Social Prob. i. 1 An American publicist..cites the mental opacity of our ruling classes as in many respects similar to the stupidity of the old French nobility.
1984 M. Faber tr. F. Nietzsche Human, All too Human v. 162 Human opacity..will..slacken the bow of all-too-taut thinking.
2. † b. The fact or condition of not reflecting light. Obsolete.
a. The state of being in shadow; darkness, dimness, obscurity; an instance of this. Also figurative.
ΘΚΠ
the mind > mental capacity > lack of understanding > stupidity, dullness of intellect > [noun]
hardnessOE
stuntnessc1000
sotshipc1050
witlessnessa1100
sotheada1200
dullness1398
bluntness1483
slowness1495
grossnessa1530
stupidity?1541
assishness?1548
dastardness1552
lourderie1555
dastardliness1556
blockishness1561
doltishness1569
sottage1569
sheepishness1574
doltry1581
sottishness1589
doltage1593
dorbellism1593
grout-headry1600
opacity1611
duncery1615
dunstery1615
stupidness1619
hebetude1621
insulsity1623
unintelligence1634
obtuseness1648
jobbernowlism1652
dullery1653
non-intelligence1653
blockheadishness1656
crassness1664
blockheadedness1716
stolidness1727
blockheadism1753
numbskullity1779
nincompoophood1791
duncishness1805
numbskullism1806
foziness1821
noodledum1821
obtusity1823
soft-headedness1823
noodledom1827
duncehood1829
dunderheadedness1830
sumphishness1830
asininity1831
dunderheadism1836
stockishness1837
dullardness1840
fat-headedness1840
stupor1845
duncedom1847
misintelligence1848
nincompoopery1850
wooden-headedness1850
dumminess1852
jolterheadedness1852
ninnyship1852
donkeyism1855
dumbness1860
beef-wittedness1863
crassitude1865
donkeyhood1869
slow-wittedness1869
chuckle-headedness1880
leatherheadedness1880
pinheadedness1884
numbskulledness1885
donkeydom1889
thickheadedness1889
density1894
moronism1922
nitwittedness1931
nitwittery1931
noodleness1931
dopiness1942
squirrel-headedness1955
nincompoopism1957
dim-wittedness1960
clottishness1961
the world > matter > light > darkness or absence of light > darkness or gloom > [noun]
thicknessc1000
dusknessa1382
umbraclec1500
duskishness1541
sadness1601
duskiness1611
gloominess1611
opacity1611
gloom1645
shadowinessa1672
dusk1700
brown1729
gloaming1832
bat-light1871
dreich1928
1611 R. Cotgrave Dict. French & Eng. Tongues Opacité, opacitie, shadinesse, vmbrage [etc.].
1646 Sir T. Browne Pseudodoxia Epidemica vi. x. 322 Their..causes; which while some ascribe unto the mixture of the Elements, others to the graduality of opacity and light.
a1677 I. Barrow Wks. (1686) III. 531 No external instruction could..penetrate those opacities of ignorance.
a1763 W. Shenstone Ess. (1806) 3 He renders the opacity of the other more discernible.
1807 J. Jebb Let. 4 Aug. in J. Jebb & A. Knox Thirty Years' Corr. (1834) I. 358 When the soul emerges from the opacities of this mortal life.
1812 G. Chalmers Hist. View Domest. Econ. Great Brit. & Ireland Pref. 13 The glimmering of the faintest dawn is more invigorating than the gloom of total opacity.
1878 T. Hardy Return of Native I. i. i. 4 The face of the heath by its mere complexion..could..intensify the opacity of a moonless midnight to a cause of shaking and dread.
1902 W. James Varieties Relig. Experience vi. 32 Fate's dark opacity.
1977 Times 23 June 16/5 The opacity of the future is darkened by the desperate twists and turns of the Liberals.
2002 Canberra Times (Nexis) 28 Sept. a18 The grey opacity of Glasgow.
ΘΚΠ
the world > matter > light > darkness or absence of light > dimness or absence of brightness > [noun]
dimnessc825
dimc1430
dunnessc1475
dullness1567
dimmedness1596
faintness1651
filminess1727
opacity1794
tenuity1794
1794 G. Adams Lect. Nat. & Exper. Philos. II. xxi. 448 Opacity..[in one sense] signifies want of transparency; in the other that no light comes from a body.
1862 J. Tyndall Mountaineering in 1861 ix. 75 It was most interesting to observe..tree after tree losing its opacity and suddenly robing itself in glory.
3.
a. The quality or condition of not transmitting light; lack of transparency or translucency; inability to be seen through; (Physics) the ratio of the intensity of the light incident on a sample or object to that of the light transmitted through it.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > [noun] > imperviousness to radiation
opacity1634
the world > matter > light > transparency or translucence > opacity > [noun]
cloudiness1594
opacity1634
umbrosity1646
opaqueness1647
opacousness1656
filminess1870
intransparency1902
the world > matter > physics > atomic nucleus > radioactivity > X-rays > [noun] > imperviousness to X-rays
opacity1634
radiopacity1917
the world > matter > light > transparency or translucence > opacity > [noun] > degree of
opacity1890
1634 H. Peacham Gentlemans Exercise (new ed.) iii. 139 As Cristall, Ice, &c. by reason of their perspicuitie..so are Quicksilver, Silver, Lead, Steele, Iron, Tin, and the like, by reason of their opacity.
1685 R. Boyle Short Mem. Hist. Mineral Waters 25 Of the Transparency, the Muddiness, or the Opacity of the Mineral Water.
1750 tr. C. Leonardus Mirror of Stones 35 Perspicuity, or opacity, occasion many differences in stones.
1814 A. Aikin Man. Mineral. Introd. 31 When the passage of light is entirely stopped opacity comes on.
1890 Jrnl. Soc. Chem. Industry 31 May 455/2 The inverse of that fraction, or I/Ix = ek a measures the opacity of the substance.
1939 Q. Jrnl. Royal Meteorol. Soc. 65 417 In the case of five stations..the summer values of opacity are higher than the winter values, owing to the prevalence of sea fogs in summer.
1972 Jrnl. Brit. Astron. Assoc. 82 147 A discussion on the opacity of the atmosphere and properties associated with the so-called ‘atmospheric windows’ [follows].
2000 Paper Technol. Feb. 17/2 Dr. Smith opened with an overview of some of the high cost pigments which are used for their functional performance, for example opacity.
b. An opaque area on or in something that is otherwise transparent or translucent.
ΘΚΠ
the world > matter > light > transparency or translucence > opacity > [noun] > opaque object or medium > opaque part or area
cloud1541
opacity1796
1796 Philos. Trans. (Royal Soc.) 87 9 A lady who had lost the sight of both [eyes], by opacities in the crystalline lenses.
1836–9 Todd's Cycl. Anat. & Physiol. II. 177/2 Slight opacities..confined to the conjunctival covering of the cornea.
1892 A. Duane tr. E. Fuchs Text-bk. Ophthalmol. viii. 371 These partial opacities embrace the equator of the inner opacity in front and behind.
1967 Brit. Jrnl. Psychiatry 113 911/2 A skull X-ray showed small calcified opacities in both hemispheres.
1990 Q. Jrnl. Med. 77 1147 A perfusion defect smaller than an opacity on radiography is less likely to indicate pulmonary embolism.
c. In extended use: inability to allow the passage of a form of radiation other than light, as sound, heat, or X-rays.
ΘΚΠ
the world > matter > physics > atomic physics > particle physics > particle avoiding strong interaction > electron > [noun] > of microscope: imperviousness to electrons
opacity1971
1879 J. Tyndall Fragm. Sci. (ed. 6) II. x. 331 Here we had the acoustic opacity of the air.
1928 F. G. Chandler & W. B. Wood Lipiodol in Diagnosis Thoracic Dis. i. 1 The properties of lipiodol are opacity to the X-rays, [etc.].
1971 Jrnl. Electron Microsc. 20 124/1 The pronounced electron opacity was localized especially..on the outer membrane.
1984 B. W. Jones Solar Syst. (BNC) 221 The dominance of thermal convection is aided by the infrared opacity of the atmosphere below 0.2 bar altitude.
1992 S. P. Maran Astron. & Astrophysics Encycl. 776/1 The kappa mechanism is an opacity increase that causes the radiation blocking.
4.
a. Philosophy and Linguistics. The property of a context of failing to preserve the truth value of a complete statement when one of its elements is replaced by a different but coreferential expression.
ΚΠ
1956 W. V. Quine in Proc. 11th Internat. Congr. Philos. 14 68 Whatever breach of extensionality it prima facie involves is shared by examples like (10) and attributable to the referential opacity of quotation.
1977 R. M. Kempson Semantic Theory ii. 15 The solution to the problem of opacity in particular remains an open one, and something of an issue for philosophers.
1990 L. Antony in G. Boolos Meaning & Method 116 The syntactic and lexical properties of mentalese expressions can..be exploited..to explain a whole range of phenomena typically classified as opacity phenomena.
b. Linguistics. Inability of a rule in phonology to be extrapolated from every occurrence of a particular phenomenon.
ΚΠ
1971 P. Kiparsky in W. O. Dingwall Surv. Ling. Sci. 621 Define the concept opacity of a rule as follows:..A rule A→B/C–D is opaque to the extent that there are surface representations of the form (i) A in environment C–D or (ii) B in environment other than C–D.
1977 Language 53 19 In each instance of opacity, a phonological rule which relates a large number of surface lexical items is obscured by the presence of other items in which the rule appears to fail.
c. Linguistics. In government and binding theory: a constraint on the grammatical contexts within which an expression can be free; spec. the property that an anaphor cannot be co-indexed with an item outside the clause containing its governing category.Although Chomsky wrote his paper On Binding in January 1978, it was not published until late 1980, hence his first published use of the term was in Rules & Representations.
ΚΠ
1980 N. Chomsky Rules & Representations iii. 91 The choice of antecedent [is governed] by a principle of ‘opacity’—variable-like elements can't be free in certain opaque domains.
1980 N. Chomsky On Binding in Linguistic Inq. 2 11 We will henceforth refer to (19) or subsequent modifications as the ‘Opacity Condition’.
1991 Canad. Jrnl. Linguistics 36 398 The structural view of transparency and opacity is used to determine where in the hierarchy a given feature may (or, more correctly, may not) occur.
1997 P. H. Matthews Conc. Oxf. Dict. Linguistics 256 The term ‘opacity’ was briefly used by Chomsky, at the end of the 1970s, for a term soon recast in Government and Binding Theory.
This entry has been updated (OED Third Edition, June 2004; most recently modified version published online June 2022).
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