The fool is a little too affected (3)
I believe the answer is:
oaf
'the fool' is the definition.
(I've seen this before)
'a little too affected' is the wordplay.
'a little' indicates a hidden word (a little bit of the clue).
'OAF' is hidden within 'too affected'.
'is' is the link.
(Other definitions for oaf that I've seen before include "Awkward stupid person" , "Idiot" , "Boor or lout" , "Lout, dullard" , "Lout; dolt" .)