Acclaimed fellow's gone outside large university, uncertain (9)
I believe the answer is:
ambiguous
'uncertain' is the definition.
(thesaurus)
'acclaimed fellow's gone outside large university' is the wordplay.
I cannot really see how this works, but
'large' could be 'big' ('big' can be a synonym of 'large') and 'big' is located in the answer.
'university' could be 'ou' and 'ou' is found within the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for ambiguous that I've seen before include "Having more than one possible meaning" , "Of uncertain meaning" , "Open to interpretation" , "cryptic" , "Equivocal" .)