Foul article on relative (7)
I believe the answer is:
unclean
'foul' is the definition.
(similar in meaning)
'article on relative' is the wordplay.
'article' becomes 'an' (indefinite article).
'on' says to put letters next to each other.
'relative' becomes 'uncle' (uncle is a kind of relative).
'an' put after 'uncle' is 'UNCLEAN'.
(Other definitions for unclean that I've seen before include "Dirty or unwashed" , "Contaminated" , "Filthy" , "Dirty, needs a wash" , "taboo" .)