Relation is given article that is dirty (7)
I believe the answer is:
unclean
'is dirty' is the definition.
(synonyms)
'relation is given article' is the wordplay.
'relation' becomes 'uncle' (uncle is a kind of relation).
'is given' says to put letters next to each other.
'article' becomes 'an' (indefinite article).
'uncle'+'an'='UNCLEAN'
'that' acts as a link.
(Other definitions for unclean that I've seen before include "Soiled like an uncle" , "Filthy" , "Contaminated" , "Infected" , "Spotted" .)