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
Rosanne	ro-ZAN (English), ro-ZAHN-nə (Dutch)	English, Dutch
Glaucia	-	Ancient Roman
Margareta	mahr-gah-RE-tah (German), MAHR-gah-re-tah (Finnish)	German, Swedish, Norwegian, Danish, Romanian, Slovene, Dutch, Finnish, Croatian
Karine (1)	ka-REEN	French
Viona	-	English (Rare)
Larissa	lə-RIS-ə (English)	English, Portuguese (Brazilian), Greek Mythology (Latinized)