Shy criminal hit in bed, I admitted (9)
I believe the answer is:
inhibited
'shy' is the definition.
(thesaurus)
'criminal hit in bed i admitted' is the wordplay.
'criminal' indicates anagramming the letters.
'admitted' indicates putting letters inside (inserted letters are admitted in).
'hit'+'in'+'bed'='hitinbed'
'hitinbed' with letters rearranged gives 'inhibted'.
'inhibted' placed around 'i' is 'INHIBITED'.
(Other definitions for inhibited that I've seen before include "Hindered, restrained" , "Hindered (an action)" , "Be hid in it (anag.)" , "Guarded" , "Constrained" .)