Filthy article relative put on (7)
I believe the answer is:
unclean
'filthy' is the definition.
('unclean' can be similar in meaning to 'filthy')
'article relative put on' is the wordplay.
'article' becomes 'an' (indefinite article).
'relative' becomes 'uncle' (uncle is a kind of relative**).
'put on' says to put letters next to each other.
'an' after 'uncle' is 'UNCLEAN'.
(Other definitions for unclean that I've seen before include "Ceremonially impure" , "Polluted" , "Soiled like an uncle" , "Dirty, ritually impure" , "Dirty, needs a wash" .)