Paint of many colours, perhaps? (4)
I believe the answer is:
coat
'paint' is the definition.
(I've seen this in other clues)
'many colours perhaps?' is the wordplay.
'many' becomes 'c' (C is the Roman numeral for o00).
'colours perhaps?' becomes 'oat' (I can't justify this - if you can you should give a lot more credence to this answer).
'c'+'oat'='COAT'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for coat that I've seen before include "Outer covering" , "Fleece" , "Apply layer" , "blanket" , "Ulster, perhaps" .)