Foul, unacceptable TV channel (7)
I believe the answer is:
offside
'foul' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'unacceptable tv channel' is the wordplay.
'unacceptable' becomes 'off' (I've seen this in other clues).
'tv channel' becomes 'side' (I've seen this before).
'off'+'side'='OFFSIDE'
Can you help me to learn more?
(Other definitions for offside that I've seen before include "Dies off in illegal soccer position" , "(In a ball game) illegally positioned" , "Illegal state in football" , "Part of vehicle furthest from kerb" , "In a position where ball can't be played (football)" .)