Toast for model (6)
I believe the answer is:
prosit
'toast' is the definition.
(I've seen this before)
'for model' is the wordplay.
'for' becomes 'pro' (I've seen this before).
'model' becomes 'sit' ('sit' can be a synonym of 'model').
'pro'+'sit'='PROSIT'
(Other definitions for prosit that I've seen before include "Good health!; tripos (anagram)" , "Good luck to you" , "(German for) cheers!" , "Happy days, perhaps" , "Sir, opt for a toast" .)