Sweep with long flourish (7)
I believe the answer is:
panache
'flourish' is the definition.
(I've seen this before)
'sweep with long' is the wordplay.
'sweep' becomes 'pan' (I've seen this before).
'with' says to put letters next to each other.
'long' becomes 'ache' (to long for something is to ache for it).
'pan'+'ache'='PANACHE'
(Other definitions for panache that I've seen before include "A confident stylish manner" , "Flamboyant confidence" , "Style, elan" , "Grand manner, theatricality" , "Distinctive elegance" .)