She's all wrong about love (4)
I believe the answer is:
lola
'she's' is the definition.
'all wrong about love' is the wordplay.
'wrong' indicates an anagram.
'about' means one lot of letters goes inside another.
'love' becomes 'o' (love means zero in tennis).
'all' is an anagram of 'lla'.
'lla' placed around 'o' is 'LOLA'.
(Other definitions for lola that I've seen before include "Whatever -- wants (song); -- Montez, mistress of Ludwig I" , "song by 4 [THE KINKS]" .)