Poet's name for a fluttering heart (5)
I believe the answer is:
dante
'poet's' is the definition.
(13th- and 14th-century Italian poet)
'name for a fluttering heart' is the wordplay.
'name' becomes 'dan' ().
'for' is a charade indicator (letters next to each other).
'heart' means to look at the middle letters.
The middle letters of 'fluttering' are 'te'.
'dan'+'te'='DANTE'
(Other definitions for dante that I've seen before include "Inferno poet" , "Thirteenth to fourteenth century Italian poet" , "Great Italian poet of 'The Divine Comedy'" , "Italian poet, writer of the Divine Comedy" , "Thirteenth-fourteenth century Italian poet" .)