Guessing to unravel what could be a hint (10)
I believe the answer is:
suggestion
'a hint' is the definition.
('suggestion' can be a synonym of 'hint')
'guessing to unravel' is the wordplay.
'unravel' indicates anagramming the letters (I've seen 'unravelling' mean this).
'guessing'+'to'='guessingto'
'guessingto' anagrammed gives 'SUGGESTION'.
'what could be' acts as a link.
(Other definitions for suggestion that I've seen before include "Hint" , "Idea put forward for consideration" , "Proposition" , "suspicion" , "one may be going to box?" .)