Head on English drink (4)
I believe the answer is:
tope
'drink' is the definition.
('tope' can be a synonym of 'drink')
'head on english' is the wordplay.
'head' becomes 'top' ('top' can be a synonym of 'head'**).
'on' says to put letters next to each other.
'english' becomes 'e' (abbreviation).
'top'+'e'='TOPE'
(Other definitions for tope that I've seen before include "plantation?" , "Drink hard regularly" , "Drink too much like poet" , "What habitual drinkers do" , "Drink to excess" .)