Quail, bird that enthrals student (6)
I believe the answer is:
flinch
'quail' is the definition.
(both can mean to show fear)
'bird that enthrals student' is the wordplay.
'bird' becomes 'finch' (finch is a kind of bird).
'that enthrals' is an insertion indicator.
'student' becomes 'L' (as in L-plates for learner drivers).
'finch' enclosing 'l' is 'FLINCH'.
(Other definitions for flinch that I've seen before include "Recoil from pain, surprise etc" , "Shrink back with fear" , "Cringe" , "Draw back in shock" , "Shy away" .)