Crush flipping miserable husband (4)
I believe the answer is:
dash
'crush' is the definition.
(thesaurus)
'flipping miserable husband' is the wordplay.
'flipping' shows that the letters should be reversed in order.
'miserable' becomes 'sad' (similar in meaning).
'husband' becomes 'h' (abbreviation).
'sad' backwards is 'das'.
'das'+'h'='DASH'
(Other definitions for dash that I've seen before include "Short line; run" , "Run hurriedly; hyphen" , "quite mild oath" , "Sprint with elan" , "Punctuation mark; hurry" .)