Smart dresser to collapse, left out (3)
I believe the answer is:
fop
'smart dresser' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'collapse left out' is the wordplay.
'collapse' becomes 'flop' (flopping is a kind of collapsing).
'left' becomes 'l' (common abbreviation).
'out' is a deletion indicator.
'flop' with 'l' taken away is 'FOP'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for fop that I've seen before include "he enjoys the finest dressing" , "Man excessively concerned with fashion" , "'Dandy, coxcomb (3)'" , "Affected dandy" , "exquisite" .)