Paint or paper I ordered is not suitable (13)
I believe the answer is:
inappropriate
'not suitable' is the definition.
(I've seen this before)
'paint or paper i ordered' is the wordplay.
'ordered' indicates an anagram.
'paint'+'or'+'paper'+'i'='paintorpaperi'
'paintorpaperi' anagrammed gives 'INAPPROPRIATE'.
'is' acts as a link.
(Other definitions for inappropriate that I've seen before include "Unsuitable" , "Not fitting" , "Unfitting" , "unfit" , "Out of place" .)