Remove fellows attending party (4)
I believe the answer is:
doff
'remove' is the definition.
(I've seen this before)
'fellows attending party' is the wordplay.
'fellows' becomes 'ff'.
'attending' says to put letters next to each other.
'party' becomes 'do' (do is a kind of party).
'ff' put after 'do' is 'DOFF'.
(Other definitions for doff that I've seen before include "shed" , "Lift (one's hat)" , "Take off hat as mark of respect" , "Remove one's cap" , "Remove, hat say" .)