Insect of character, say (3)
I believe the answer is:
bee
'insect' is the definition.
(bee is a type of insect)
'character say' is the wordplay.
'character' becomes 'b'.
'say' shows a homophone (sound like).
'b' sounds like 'BEE'.
'of' is the link.
(Other definitions for bee that I've seen before include "Apian insect" , "Useful insect" , "Stinging insect" , "Hymenopterous insect" , "A honey-maker" .)