Insect of biting nature (4)
I believe the answer is:
gnat
'insect' is the definition.
(gnat is a kind of insect)
'of biting nature' is the wordplay.
'of' indicates the answer is hidden within the clue.
'GNAT' is hidden in the letters of 'biting nature'.
(Other definitions for gnat that I've seen before include "Small biting flying insect" , "small irritant" , "Biting pest" , "Small biter" , "Small bloodsucker" .)