Head in large cask turned up (3)
I believe the answer is:
nut
'head' is the definition.
(informal term for somebody's head)
'large cask turned up' is the wordplay.
'large cask' becomes 'tun' (type of container for alcohol).
'turned up' says the letters should be written in reverse.
'tun' backwards is 'NUT'.
'in' acts as a link.
(Other definitions for nut that I've seen before include "Mechanical fastener" , "eccentric type" , "eg Pecan" , "keen admirer" , "Bolt securer" .)