Slightly injure fly (4)
I believe the answer is:
wing
'fly' is the definition.
(I know that fly can be written as wing)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for wing that I've seen before include "Wound, but not fatally" , "Wound superficially; part of large house" , "Part of flier" , "Plovery flock" , "Chicken portion" .)