Drink in the bar regularly (3)
I believe the answer is:
tea
'drink' is the definition.
(tea is a drink)
'the bar regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'the'+'bar'='thebar'
The alternate letters of 'thebar' are 'TEA'.
'in' is the link.
(Other definitions for tea that I've seen before include "Popular drink" , "Char" , "Early evening meal" , "Darjeeling, e.g." , "Cha" .)