Silence after bachelor’s party (4)
I believe the answer is:
bash
'party' is the definition.
(term for a party or celebration)
'silence after bachelor's' is the wordplay.
'silence' becomes 'sh' ('sh' is said to tell someone to be silent).
'after' says to put letters next to each other.
'bachelor' becomes 'BA' (the qualification: Bachelor of Arts).
'sh' after 'ba' is 'BASH'.
(Other definitions for bash that I've seen before include "Batter" , "knock" , "Party - clobber" , "Dent - party" , "Social event - clobber" .)