No one takes part - it's disgusting (7)
I believe the answer is:
noisome
'disgusting' is the definition.
(I've seen this in another clue)
'no one takes part' is the wordplay.
'one' becomes 'i' (Roman numeral).
'takes' is a charade indicator (letters next to each other).
'part' becomes 'some' (I've seen this before).
'no'+'i'+'some'='NOISOME'
'it's' is the link.
(Other definitions for noisome that I've seen before include "Moonies (anag.)" , "Smelling bad" , "Nauseating" , "Foul; putrid" , "injurious to health" .)