Need to get drunk before day is over (5)
I believe the answer is:
ended
'over' is the definition.
('ended' can be a synonym of 'over')
'need to get drunk before day' is the wordplay.
'to get drunk' indicates an anagram.
'before' says to put letters next to each other.
'day' becomes 'd'.
'need' with letters rearranged gives 'ende'.
'ende'+'d'='ENDED'
'is' acts as a link.
(Other definitions for ended that I've seen before include "Brought to a finish" , "Culminated" , "Done" , "Brought to a close" , "Acclaim" .)