Sort of swallow one drink (7)
I believe the answer is:
martini
'drink' is the definition.
(martini is a kind of drink)
'sort of swallow one' is the wordplay.
'sort of swallow' becomes 'martin'.
'one' becomes 'i' (Roman numeral).
'martin'+'i'='MARTINI'
(Other definitions for martini that I've seen before include "obtained from a bottle" , "Cocktail of gin and dry vermouth" , "alcoholic drink" , "Italian drink" , "tipple" .)