work nights
To work in the evenings, as opposed to during the day. I used to work nights, but it took such a toll on my sleeping that I switched back to the day shift.
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!
work (one's) magic
To use one's unique talents or charm to obtain a desired thing or outcome. I never thought the boss would approve our business trip, but Sam worked her magic, and now, we're off to Denver! Whenever I can't get my car running, I have my dad come over and work his magic on the engine.
work the crowd
To excite or entertain an audience. Man, that singer sure knows how to work a crowd! They're going wild for him! The keynote speaker was late, so I had to work the crowd for a while to stall.
work the room
To interact with many people at an event or function. Often, but not always, applied to business situations. At networking events, Ben totally works the room, with the goal of meeting as many people as he possibly can. At parties, my dad always works the room and chats with everyone, but I'm too shy for that.
work (one's) way through
To stay engaged in a task continuously. Often used when the task is long-term or plodding. Kate is working her way through college, but it's taken a while, as she's only been able to attend classes part-time. I have to work my way through any book I start, even if I don't like it very much.
working girl
A prostitute. The vice squad always patrols this area, looking to arrest any working girls on the street.
in working order
Of a machine, functional; not broken. I just picked up my car from the shop, and it's in working order again, thank goodness!
work the oracle
To manipulate something for one's personal gain (often financially). Primarily heard in UK. In order to win that much money gambling, he must have worked the oracle.
work up to the collar
To work hard; to exert oneself. This now-outdated phrase refers to the collar on a beast of burden. I ended up doing most of the project myself because I didn't trust my partner to work up to the collar—he's lazy.
a working over
A harsh reprimand, often one that lasts a lengthy amount of time. She gave her teenage daughter a good working over for breaking curfew. I got a good working over from the professor after I submitted my project late.