Appropriate side (5)
I believe the answer is:
right
This clue is a double definition.
'appropriate' is the first definition.
(I've seen this before)
'side' is the second definition.
(Other definitions for right that I've seen before include "One has a claim to be correct" , "Morally good; rectify" , "Genuine" , "''The customer is always .....''" , "Girth (anag)" .)