Belief constant over consuming wine (5)
I believe the answer is:
credo
'belief' is the definition.
(credo is a kind of belief)
'constant over consuming wine' is the wordplay.
'constant over' becomes 'co' (this could be a standard abbreviation I've not previously seen).
'consuming' is an insertion indicator.
'wine' becomes 'red' (red wine is a kind of wine).
'co' enclosing 'red' is 'CREDO'.
Can you help me to learn more?
(Other definitions for credo that I've seen before include "Belief system" , "Mass movement" , "Apostles' beliefs" , "Formal statement of beliefs" , "ideology" .)