Some alkies press on for drink (8)
I believe the answer is:
espresso
'drink' is the definition.
(espresso is a kind of drink)
'some alkies press on' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'ESPRESSO' can be found hidden inside 'alkies press on'.
'for' is the link.
(Other definitions for espresso that I've seen before include "Coffee (S, not X)" , "Coffee drink" , "Seep Ross into the coffee" , "Coffee made by forcing steam through grounds" , "strong drink" .)