Come across softly with large force (6)
I believe the answer is:
compel
'force' is the definition.
(I've seen this before)
'come across softly with large' is the wordplay.
'across' means one lot of letters goes inside another.
'softly' becomes 'p' (short for piano, musical term for softly).
'with' means one lot of letters go next to another.
'large' becomes 'l'.
'come' enclosing 'p' is 'compe'.
'compe'+'l'='COMPEL'
(Other definitions for compel that I've seen before include "drive on" , "Bring about by force" , "Use force or influence to make person do something" , "Make someone do something" , "Force, oblige to do something" .)