Fit? Quite possibly (4)
I believe the answer is:
well
I believe this is a triple definition!
'fit?' is the first definition.
('well' is associated in meaning with 'fit')
'quite' is the second definition.
(thesaurus)
'possibly' is the third definition.
(thesaurus)
(Other definitions for well that I've seen before include "Healthy; extremely" , "We shall" , "Bore; extremely" , "Source; in good health" , "all right" .)