Defrauded Conservative getting very cross (7)
I believe the answer is:
cheated
'defrauded' is the definition.
(cheat can mean to defraud)
'conservative getting very cross' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'getting' means one lot of letters go next to another.
'very cross' becomes 'heated' (heated can mean very angry).
'c'+'heated'='CHEATED'
(Other definitions for cheated that I've seen before include "taken for a ride" , "Defeated through deceit" , "Behaved dishonestly" , "stung" .)