Excite stylish sweetheart (7)
I believe the answer is:
inflame
'excite' is the definition.
(I've seen this before)
'stylish sweetheart' is the wordplay.
'stylish' becomes 'in'.
'sweetheart' becomes 'flame' (I've seen this before).
'in'+'flame'='INFLAME'
(Other definitions for inflame that I've seen before include "Exacerbate" , "Bother" , "Make (a situation) worse" , "Intensify, aggravate" , "Incite" .)