Swell to fortissimo (4)

I believe the answer is:

toff

'swell' is the definition.
(wealthy or high-class person)

'to fortissimo' is the wordplay.
'fortissimo' becomes 'ff'.
'to'+'ff'='TOFF'

(Other definitions for toff that I've seen before include "One could be stuck up" , "Posh bloke (sl)" , "In slang, a posh person" , "Posh chap" , "Posh type" .)

I've seen this clue in The Sun, The Independent, The Telegraph and The Globe and Mail.

Want a hint initially instead of a full solution? Install my app