Dapper tenor on edge (4)
I believe the answer is:
trim
'dapper' is the definition.
(thesaurus)
'tenor on edge' is the wordplay.
'tenor' becomes 't'.
'on' says to put letters next to each other.
'edge' becomes 'rim' (rim is a kind of edge).
't'+'rim'='TRIM'
(Other definitions for trim that I've seen before include "Cut off excess, make neat" , "Fit - pare" , "Clip into shape" , "Make hair neat using scissors" , "Neat - pare" .)