He's not out of US Cabinet (4)
I believe the answer is:
scab
'he's not out' is the definition.
(I've seen this before)
'of us cabinet' is the wordplay.
'of' indicates a hidden word.
'SCAB' is hidden in the letters of 'us cabinet'.
(Other definitions for scab that I've seen before include "He's not out" , "evidence of recent injury" , "he refuses to come out" , "Blackleg - sign of injury" , "sign of wound healing" .)