di·min·ish 
(dĭ-mĭnĭsh)
(dĭ-mĭnĭsh)v. di·min·ished, di·min·ish·ing, di·min·ish·es
v.tr.
1.
a. To make smaller or less; reduce or lessen. See Synonyms at decrease.
b. To detract from the authority, reputation, or prestige of: "Her upper-class perfection ... somehow diminished me" (Shirley Abbott).
2. To cause to taper.
3. Music To reduce (a perfect or minor interval) by a semitone.
v.intr.
1. To become smaller or less.
2. To taper.
[Middle English diminishen, blend of diminuen, to lessen (from Old French diminuer, from Latin dīminuere, variant of dēminuere : dē-, de- + minuere, to lessen) and minishen, to reduce (from Old French minuiser, from Vulgar Latin *minūtiāre, from Latin minūtia, smallness, from minūtus, small, from past participle of minuere); see mei-2 in the Appendix of Indo-European roots.]
di·minish·a·ble adj.
di·minish·ment n.