Insect sounds like a character (3)
I believe the answer is:
bee
'insect' is the definition.
(bee is a type of insect)
'sounds like a character' is the wordplay.
'sounds like' shows a homophone (sound like).
'a character' becomes 'B'.
'b' sounds like 'BEE'.
(Other definitions for bee that I've seen before include "See 17" , "Busy buzzer" , "Hymenopterous insect" , "Honey maker" , "Hive worker" .)