Conventional — flavour (7)
I believe the answer is:
vanilla
I believe this clue is a double definition.
'conventional' is the first definition.
(I've seen this before)
'flavour' is the second definition.
(vanilla is a type of flavour)
(Other definitions for vanilla that I've seen before include "Flavouring from pod of certain orchids" , "without additions" , "type of orchid" , "Nice flavouring for ice-cream" , "Orchid, its pod, bean for flavouring" .)