Clown that is sacrificing love (4)
I believe the answer is:
twit
'clown' is the definition.
'that is sacrificing love' is the wordplay.
'that is' becomes 'towit' ('to wit' can mean 'namely' or 'that is').
'sacrificing' suggests deleting specific letters.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'towit' with 'o' taken away is 'TWIT'.
(Other definitions for twit that I've seen before include "Bait - fool" , "dunce" , "Stupid person" , "Silly fool" , "Nincompoop" .)