Squander money in buffet (4)
I believe the answer is:
blow
I believe this is a double definition.
'squander money' is the first definition.
(blowing money is wasting it)
'buffet' is the second definition.
(both can mean to hit)
'in' acts as a link.
(Other definitions for blow that I've seen before include "Bang, wallop" , "haymaker, perhaps" , "Clip" , "Shock; sound (a horn)" , "Sudden misfortune" .)