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
Longinus	-	Ancient Roman
Agnes	AG-nəs (English), AHK-nes (German), AHKH-nəs (Dutch), AHNG-nes (Swedish)	English, German, Dutch, Swedish, Norwegian, Danish, Icelandic, Ancient Greek (Latinized)
Romeo	-	Italian
Thaddaeus	-	Biblical
Raijin	ṙah-ee-jeen (Japanese)	Far Eastern Mythology
Enes	-	Turkish, Bosnian