Decline drink and go (8)
I believe the answer is:
downturn
'decline' is the definition.
(I've seen this before)
'drink and go' is the wordplay.
'drink' becomes 'down' (downing is a kind of drinking).
'and' says to put letters next to each other.
'go' becomes 'turn' ('turn' can be a synonym of 'go'**).
'down'+'turn'='DOWNTURN'
(Other definitions for downturn that I've seen before include "Decline eg of economic activity" , "Reduction in business" , "Decline in business" , "Deterioration" , "Worsening of economic activity" .)