Posh seasoning? (5)
I believe the answer is:
spice
'seasoning?' is the definition.
(I know that spice is a type of seasoning)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for spice that I've seen before include "Flavouring substance" , "It creates added interest" , "Aromatic flavouring" , "Pungent flavouring" , "Something providing excitement" .)