Completely enthusiastic about spinner? Not quite (2,4)
I believe the answer is:
in toto
'completely' is the definition.
(thesaurus)
'enthusiastic about spinner? not quite' is the wordplay.
'enthusiastic about' becomes 'into' (I've seen this before).
'spinner?' becomes 'top' (something that spins).
'not quite' means to remove the last letter.
'top' with its final letter taken off is 'to'.
'into'+'to'='IN TOTO'
(Other definitions for in toto that I've seen before include "Tranquillity" , "Completely - entirely (Latin)" , "Altogether, completely" , "As a whole (Latin)" , "Wholly" .)