Come across for hearing — guilty party may be this (5)
I believe the answer is:
fined
'guilty party may be this' is the definition.
(a fine is a type of punishment)
'come across for hearing' is the wordplay.
'come across' becomes 'find' (synonyms).
'for hearing' shows a homophone (sound like).
'find' sounds like 'FINED'.
(Other definitions for fined that I've seen before include "Ordered to pay penalty" , "Mulcted" , "Imposed financial penalty on" , "Fed in (anag.)" .)