Some Scots wi' glasses drink (4)
I believe the answer is:
swig
'drink' is the definition.
(swigging is a kind of drinking)
'some scots wi' glasses' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'SWIG' can be found hidden inside 'scots wi glasses'.
(Other definitions for swig that I've seen before include "Slug" , "(Take) quick drink from bottle" , "Swallow (drink) greedily" , "Large draught of drink" , "Drink in large draughts" .)