Team unhappy about question (5)
I believe the answer is:
squad
'team' is the definition.
('squad' can be a synonym of 'team')
'unhappy about question' is the wordplay.
'unhappy' becomes 'sad' ('sad' can be a synonym of 'unhappy').
'about' means one lot of letters goes inside another.
'question' becomes 'qu'.
'sad' placed around 'qu' is 'SQUAD'.
(Other definitions for squad that I've seen before include "Small military unit" , "Cooperative unit" , "Body of soldiers" , "Team plus reserves" , "Smallest army unit" .)