Topless model is more than enough (5)
I believe the answer is:
ample
'more than enough' is the definition.
(I've seen this before)
'topless model' is the wordplay.
'topless' means to remove the first letter.
'model' becomes 'sample' (model can mean a prototype or sample).
'sample' with its first letter taken off is 'AMPLE'.
'is' acts as a link.
(Other definitions for ample that I've seen before include "Easily sufficient" , "Sealed glass container for dose of medicine" , "Large, capacious" , "Spacious" , "Plenteous" .)