Play in panto yearly (3)
I believe the answer is:
toy
'play' is the definition.
('toy' can be a synonym of 'play')
'in panto yearly' is the wordplay.
'in' says the answer is hidden in the clue.
'TOY' is hidden in the letters of 'panto yearly'.
(Other definitions for toy that I've seen before include "Doll or teddy, say" , "One of spelt out words" , "Miniature (dog)" , "Small breed" , "A child's plaything" .)