Fleeting, transitory; evanescent, unsubstantial. Obsolete.

Of or belonging to the air; aerial; (hence) ethereal, spiritual, incorporeal, insubstantial. Also: open to the air. Cf. airy, adj.

figurative. Without a firm foundation, baseless. Obsolete.

figurative. Of persons and things: wanting soundness, solidity, or substance; empty, vain; not answering inwardly to outward appearance; insincere…

flitting about, fluttering; trembling; †shifting, unstable, fleeting.

That is diminishing or becoming weak; fading, vanishing.

Ethereal, insubstantial, immaterial; (also) unreal, imaginary; fanciful, other-worldly.

Lacking in solid or substantial qualities.

Fleeting, shifting; light, airy, unsubstantial.

Having ‘nothing in it’, ‘airy’, intangible, empty, unsubstantial, flimsy, vain, frivolous, trifling, worthless. (Often passing into other senses; see…

Of an abstract concept or quality: insubstantial, superficial.

Thin in physical consistency; sparse; rare, rarified, subtile; unsubstantial.

Having no bodily or material substance.

figurative with various connotations: ‘Swelling’, ‘working’; light and superficial, ‘frothy’.

Lacking the character of a thing; insubstantial. rare.

depreciative. Like air in its (apparently) intangible or empty character. Insubstantial; imaginary; slight, inconsequential.

Lacking body or substance; flimsy, thin.

figurative. Deficient in substance or solidity.

Void of substance; not of stout or solid substance; unsubstantial. Also figurative.

Not having an underlying basis or foundation, groundless; unjustifiable.

transferred and figurative. Wanting body or substance; unsubstantial; intangible. Also in to vanish (melt,etc.) into thin air: to disappear…

Not solid; unsubstantial; weak, flimsy, light, unstable.

Not composed of (material) substance.

= tenuous, adj. 2.

Designating something fragile, insubstantial, or delusive; esp. with reference to fraudulent commercial undertakings, as bubble scheme, etc. Cf…

Spun thinly; drawn out in spinning to a slender thread. Also figurative.

Of, relating to, or consisting of wind; spec. like the wind in its (apparently) intangible or empty character; insubstantial, empty. Obsolete.

(un-, prefix1 affix 2.)

Confectionery, etc. Beaten into a froth: see whip, v. 7. Hence in figurative expressions denoting something ‘frothy’, flimsy, or unsubstantial.

= aerial, adj. 7.

figurative. Airy, unsubstantial. Obsolete.

Unsubstantial, rotten, trashy.

Bad, inferior, substandard, worthless. In Scottish use also: unsubstantial, insignificant. Cf. noughty, adj. 3b. Obsolete.

Without or devoid of substance; unsubstantial.

figurative. Unsubstantial, indefinite, vague.

figurative. Insubstantial, intangible, unreal; (also) dainty, delicate. rare.

Made airy; affectedly superior, given to assuming airs.

(cf. blow, v.1 12a), susceptible to the influence of a current of air, hence fragile; also figurative.

Not substantial; not consisting of matter, incorporeal.

(un-, prefix1 affix 2.)

Elusive, evanescent.

Wanting in ‘stuff’ or substance.

Without substance, baseless.

Extremely light (in various senses); esp. insubstantial, inconsequential; very subtle or delicate.