Finish off the job? (7)
I believe the answer is:
'finish off' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for execute that I've seen before include "Carry out - official killing?" , "Put to death - put into effect" , "Inflict capital punishment upon" , "Perform or kill legally" , "Put to death or carry out, say plan" .)