Told that denim is wrong for inside (8)
I believe the answer is:
informed
'told' is the definition.
(I've seen this before)
'denim is wrong for inside' is the wordplay.
'is wrong' indicates anagramming the letters.
'inside' means one lot of letters goes inside another.
'denim' anagrammed gives 'inmed'.
'inmed' enclosing 'for' is 'INFORMED'.
'that' is the link.
(Other definitions for informed that I've seen before include "Expert" , "Knowledgeable or briefed" , "Imparted knowledge" , "Passed on knowledge" , "Told" .)