Tutor cooked fish (5)
I believe the answer is:
trout
'fish' is the definition.
(I know that trout is a type of fish)
'tutor cooked' is the wordplay.
'cooked' indicates anagramming the letters (letters cooked into a new form).
'tutor' with letters rearranged gives 'TROUT'.
(Other definitions for trout that I've seen before include "Small salmonlike fish" , "Prized river fish" , "tickled to death?" , "Commonly caught fish" , "Rainbow, for example" .)