Avoid early retirement! (3,2)
I believe the answer is:
sit up
'avoid' is the definition.
Although both the answer and definition are verbs in their base form, I cannot understand how they can define each other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for sit up that I've seen before include "Pay attention - . . . . . and take notice" , "Keep-fit movement" , "Abdominal exercise" , "postpone retirement" , "physical exercise" .)