Certainly getting in drink is considered (8)
I believe the answer is:
measured
'is considered' is the definition.
(thesaurus)
'certainly getting in drink' is the wordplay.
'certainly' becomes 'sure' (synonyms).
'getting in' means one lot of letters goes inside another.
'drink' becomes 'mead' (mead is a kind of drink).
'sure' placed inside 'mead' is 'MEASURED'.
(Other definitions for measured that I've seen before include "Determine dimensions" , "Unhurried and with care and dignity" , "Weighed" , "Dare Muse be regular in movement" , "Having a slow and regular rhythm" .)