up and (do something)

To do something quickly, unexpectedly, or abruptly, especially without warning or explanation. I must have offended him, because halfway through the conversation he just up and left. The town has been in a panic searching for a young girl who up and vanished over the weekend. Everyone asks how I came up with the story, thinking it must have taken all this time and planning, but the truth is one day I thought up the premise and then I just up and wrote it.

up and about

Moving around, especially after a period of injury, illness, or inactivity. After months in a cast, I'm finally up and about again, thank goodness! The surgery went very well, and the doctor is optimistic that she'll be up and about soon. We're all thrilled to be up and about after seven hours on a bus!

up and about/doing

Resuming activity, especially after a rest or an illness. These terms seem to be American in origin. One appears as an exhortation in the tireless Benjamin Franklin’s Poor Richard’s Almanack (1755): “The Day is short, the Work great, the Workman lazy, the Wages high, the Master urgeth; Up, then, and be doing.”