Model gun is toy (6)
I believe the answer is:
trifle
'is toy' is the definition.
(both can mean to play with)
'model gun' is the wordplay.
'model' becomes 't' (Ford Model T car).
'gun' becomes 'rifle' (rifle is a kind of gun).
't'+'rifle'='TRIFLE'
(Other definitions for trifle that I've seen before include "Not much" , "Treat frivolously" , "Possible component of meal" , "Pudding - bagatelle" , "more than half of 13 [AFTERSHAVE], for example" .)