Beat or push in, possibly (6)
I believe the answer is:
punish
'beat' is the definition.
(I've seen this before)
'push in possibly' is the wordplay.
'possibly' is an anagram indicator.
'push'+'in'='pushin'
'pushin' is an anagram of 'PUNISH'.
'or' is the link.
(Other definitions for punish that I've seen before include "exact retribution" , "Mete out penalty to" , "Discipline" , "Sentence" , "Castigate" .)