To leave, and return in a short time.
I'm just popping off to the shops to pick up some bread.
To die suddenly.
To kill someone.
(usually derogatory) To speak frankly.
popping off at the mouth
To release flatulence, in most cases, in short rapid succession.
To thrust away, or put off promptly.
to pop one off with a denial
To turn off.
Pop that light off, will you?
To do very well.
You really popped off last night!