Love bird (4)
I believe the answer is:
duck
I believe this clue is a double definition.
'love' is the first definition.
(love and duck mean zero in tennis and cricket)
'bird' is the second definition.
(I know that duck is a type of bird)
(Other definitions for duck that I've seen before include "sporting failure" , "Dip" , "strong cloth" , "strong fabric" , "Part of pair" .)