Exclude nothing embracing sweetheart for party (5)
I believe the answer is:
beano
'for party' is the definition.
(I've seen this before)
'exclude nothing embracing sweetheart' is the wordplay.
'exclude' becomes 'ban' (I've seen this in another clue).
'nothing' becomes 'O' (looks like zero - 0).
'embracing' means one lot of letters goes inside another.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'ban'+'o'='bano'
'bano' enclosing 'e' is 'BEANO'.
(Other definitions for beano that I've seen before include "Informal party" , "Function" , "A bone for a feast" , "Comic - party" , "Enjoyable party" .)