Limit the drink; it makes good sense (9)
I believe the answer is:
rationale
'it makes good sense' is the definition.
The definition suggests a singular noun which matches the answer.
'limit the drink' is the wordplay.
'limit' becomes 'ration' (rationing is a kind of limiting).
'the drink' becomes 'ale' (type of beer).
'ration'+'ale'='RATIONALE'
Can you help me to learn more?
(Other definitions for rationale that I've seen before include "Philosophy" , "Logical reason for action" , "Reasoned exposition" , "Good reason" , "Why regulate" .)