Remain in a post-operative condition (4)
I believe the answer is:
stop
'remain' is the definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'in a post-operative condition' is the wordplay.
'in' says the answer is hidden in the clue.
'STOP' is hidden in the letters of 'post operative condition'.
Can you help me to learn more?
(Other definitions for stop that I've seen before include "Withhold payment" , "Post (anag.)" , "Stay" , "Don't allow" , "Block; end; group of organ pipes" .)