Whip dismissed by party (5)
I believe the answer is:
outdo
'whip' is the definition.
(thesaurus)
'dismissed by party' is the wordplay.
'dismissed' becomes 'out' (dismissed in cricket).
'by' says to put letters next to each other.
'party' becomes 'do' (do is a kind of party).
'out'+'do'='OUTDO'
(Other definitions for outdo that I've seen before include "Cap" , "Overcome" , "Exceed" , "Perform better than (someone)" , "going to top?" .)