Unhappy when divided (3,2)
I believe the answer is:
cut up
'unhappy' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I don't see?
'divided' is the wordplay.
I cannot really see how this works, but
'divided' could be 'cut' and 'cut' is found in the answer.
The remaining letters 'up' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'when' is the link.
Can you help me to learn more?
(Other definitions for cut up that I've seen before include "Sliced; distressed" , "Happy? No" , "so treated by another driver?" , "Abrupt change; pace" , "Chop into bits - deeply offended" .)