Hooligan was left out (4)
I believe the answer is:
lout
'hooligan' is the definition.
(thesaurus)
'left out' is the wordplay.
'left' becomes 'l' (common abbreviation).
'l'+'out'='LOUT'
'was' acts as a link.
(Other definitions for lout that I've seen before include "Yob" , "A coarse ignorant fellow" , "Boor, oaf" , "Ill-mannered or aggressive man" , "Lob" .)