Offer in favour of model (7)
I believe the answer is:
propose
'offer' is the definition.
(as in proposing an idea)
'in favour of model' is the wordplay.
'in favour of' becomes 'pro' (being pro a particular cause).
'model' becomes 'pose' (synonyms).
'pro'+'pose'='PROPOSE'
(Other definitions for propose that I've seen before include "Make an offer of marriage" , "Intend" , "Request" , "table" , "Put forward for consideration" .)