/ Dictionary / Index A attaboy: Meaning and Definition of Find definitions for: at•ta•boy Pronunciation: (at'u-boi"), [key] — interj. Informal. (used as an enthusiastic expression of encouragement or approval to a boy, man, or male animal.) Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. att. attacca Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language