work (one's) butt off

(redirected from worked their butts off)

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!
See also: butt, off, work