Figure a flier is not one to be trusted (5)
I believe the answer is:
crook
'not one to be trusted' is the definition.
I can't judge whether this defines the answer.
'figure a flier' is the wordplay.
'figure' becomes 'c' (I've seen this in other clues).
'a flier' becomes 'rook' (rook is a kind of birdanimal).
'c'+'rook'='CROOK'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for crook that I've seen before include "Bend; criminal; staff" , "Hooked staff" , "Professional criminal" , "Shepherd's staff" , "Twister" .)