Crazy rackets (4)
I believe the answer is:
bats
This clue is a double definition.
'crazy' is the first definition.
(bats can informally mean crazy)
'rackets' is the second definition.
(I know this)
(Other definitions for bats that I've seen before include "Mad - clubs" , "Those striking" , "Very eccentric" , "Mad - nocturnal creatures" , "Crazy; night-fliers" .)