Shy and stupid? Take it back! (5)
I believe the answer is:
timid
'shy' is the definition.
(I know that shy can be written as timid)
'stupid? take it back' is the wordplay.
'stupid?' becomes 'dim' ('dim' can be similar in meaning to 'stupid').
'take' is a charade indicator (letters next to each other).
'back' is a reversal indicator.
'dim'+'it'='dimit'
'dimit' backwards is 'TIMID'.
'and' is the link.
(Other definitions for timid that I've seen before include "afraid to speak out?" , "Easily alarmed, shy" , "Fearful - shy" , "Diffident, faint-hearted" , "not forward" .)