Something to ultimately play with (3)
I believe the answer is:
toy
'play with' is the definition.
(thesaurus)
'something to ultimately' is the wordplay.
I cannot quite see how this works, but
'to' is present in the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for toy that I've seen before include "One of spelt out words" , "Trifle or dally with" , "Doll or teddy, say" , "Small breed" , "Child's amusement" .)