Lazy model, cast (7)
I believe the answer is:
workshy
'lazy' is the definition.
(synonyms)
'model cast' is the wordplay.
'model' becomes 'work' (I can't explain this - if you can you should believe this answer much more).
'cast' becomes 'shy' (both can mean to throw or fling).
'work'+'shy'='WORKSHY'
Can you help me to learn more?
(Other definitions for workshy that I've seen before include "Having malingering tendencies?" , "Lazy and idle" , "Avoiding labour, lazy" , "Inclined to laziness" , "Inclined to stay at home?" .)