/ Dictionary / Index A aggress: Meaning and Definition of Find definitions for: ag•gress Pronunciation: (u-gres'), [key] — v.i. to commit the first act of hostility or offense; attack first. to begin to quarrel. —v.t. to behave aggressively toward; attack (often fol. by upon): wild animals aggressing their prey. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: aggress (Thesaurus) aggregative aggression Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language