interjection Informal.

(used as an enthusiastic expression of encouragement or approval to a boy, man, or male animal.)

Origin of attaboy

1905–10, Americanism; alleged to be a reduced form of that's a boy or that's the boy Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for attaboy

Contemporary Examples of attaboy

Historical Examples of attaboy

  • In the ominous silence a cracked voice yelped: "Attaboy Fenton!"

    Vulcan's Workshop

    Harl Vincent

  • It will be observed that Mr. Burke has given his attaboy a "t" too many.

    Pieces of Hate

    Heywood Broun

  • He did go and support the team, and enhance the glory of Zenith, by yelling "Attaboy!"


    Sinclair Lewis

British Dictionary definitions for attaboy


sentence substitute

slang, mainly US an expression of approval or exhortation
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for attaboy

1909, probably from common pronunciation of "that's the boy!" a cheer of encouragement or approval.

Online Etymology Dictionary, © 2010 Douglas Harper