work (one's) butt off

To work really hard (on or at something). I know you thought it was just a silly New Year's resolution, but I've been working my butt off at the gym! Sally and Jim work their butts off when we hold our user conference—I don't know what I'd do without them!

Common Names:

Name	Pronounced	Usage
Jacobus	yah-KO-bus (Dutch)	Dutch, Late Roman
Ethelbert	-	English
Nnamdi	-	Western African, Igbo
Alisha	ə-LISH-ə, ə-LEE-shə	English
Dionysodoros	-	Ancient Greek
Zisel	-	Yiddish