The fathead scoffed the lot! (4)
I believe the answer is:
fate
'the lot' is the definition.
('fate' can be a synonym of 'lot')
'the fathead scoffed' is the wordplay.
'the fathead' becomes 'f' (head letter of 'fat').
'scoffed' becomes 'ate' ('to scoff' is to eat).
'f'+'ate'='FATE'
(Other definitions for fate that I've seen before include "One's lot" , "Fortune" , "Predestiny" , "Lady luck" , "Lot -- doom" .)