Naive and easily tricked (8)
I believe the answer is:
gullible
'naive and easily tricked' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for gullible that I've seen before include "Easily deceived, naive" , "Credulous, easily deceived" , "Naive and easily tricked" , "Easily fooled" , "Easily taken in, too quick to believe" .)