Foiled awful fraudster — about time (10)
I believe the answer is:
frustrated
'foiled' is the definition.
('frustrate' can be a synonym of 'foil')
'awful fraudster about time' is the wordplay.
'awful' is an anagram indicator.
'about' is an insertion indicator.
'time' becomes 't'.
'fraudster' anagrammed gives 'frustraed'.
'frustraed' enclosing 't' is 'FRUSTRATED'.
(Other definitions for frustrated that I've seen before include "Disheartened" , "Prevented from progressing" , "Thwarted" , "Disappointingly unsuccessful" , "Having a sense of discouragement and dissatisfaction" .)