To admit defeat or plead for mercy, especially in an informal physical contest of some kind. The brothers often play fought, but it was invariably the younger of the two who had to holler uncle by the end.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
holler uncleand cry uncle; say uncle
Fig. to admit defeat. Joe kept pounding on Jim, trying to get him to holler uncle. He twisted my arm until I cried uncle.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.