Upset husband in public squabble (9)
I believe the answer is:
overthrow
'upset' is the definition.
('overthrow' can be a synonym of 'upset')
'husband in public squabble' is the wordplay.
'husband' becomes 'h'.
'in' is an insertion indicator.
'public' becomes 'overt' ('overt' is associated in meaning with 'public').
'squabble' becomes 'row' (I've seen this in other clues).
'overt'+'row'='overtrow'
'h' put inside 'overtrow' is 'OVERTHROW'.
(Other definitions for overthrow that I've seen before include "Unexpected run" , "Dethrone or oust" , "Vanquish" , "Bring down (government)" , "caused discomfiture" .)