Model or green fur (5)
I believe the answer is:
mould
'model' is the definition.
(synonyms)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for mould that I've seen before include "Guide or control the development of" , "Crumbly soil" , "jelly?" , "Influence" , "Mildew" .)