Work given to model is a con (7)
I believe the answer is:
opposer
'a con' is the definition.
(thesaurus)
'work given to model' is the wordplay.
'work' becomes 'op' (common abbreviation for 'opus').
'given to' says to put letters next to each other.
'model' becomes 'poser' (synonyms).
'op'+'poser'='OPPOSER'
'is' is the link.
(Other definitions for opposer that I've seen before include "Adversary" , "Contender" , "The one against the motion" , "Person against the motion" , "One offering resistance" .)