Watch bishop abandoning deal (5)
I believe the answer is:
timer
'watch' is the definition.
(a watch might be used to time something)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for timer that I've seen before include "Stopwatch, say" , "Remit for, say, measuring device - or the measurer (5)" , "Pre-set switch" , "Recorder of duration" , "Preset activator" .)