Bear coming back as child's plaything (4)
I believe the answer is:
hoop
'child's plaything' is the definition.
(I've seen this in another clue)
'bear coming back' is the wordplay.
'bear' becomes 'pooh' (Winnie the Pooh).
'coming back' says the letters should be written in reverse.
'pooh' in reverse letter order is 'HOOP'.
'as' acts as a link.
(Other definitions for hoop that I've seen before include "Arch used in croquet" , "Circular band, in basketball, say" , "Wood, metal or plastic band" , "Ring of wood - arch at croquet" , "children's toy" .)