Teacher's favorite (3)
I believe the answer is:
pet
'teacher's favorite' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for pet that I've seen before include "Bad humour; darling" , "Caress - budgie, perhaps?" , "Darling; fit of sulks" , "Loved domestic animal" , "Preferred" .)