/ Dictionary / Index A amentia: Meaning and Definition of Find definitions for: a•men•tia Pronunciation: (ā-men'shu, u-men'-), [key] — n. Psychiatry. lack of intellectual development; imbecility; severe mental retardation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: amentia (Thesaurus) amentaceous amentiferous Related Content Daily Word Quiz: loquacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language