Suffer pain cursing secretly (5)
I believe the answer is:
incur
'suffer' is the definition.
(I've seen this before)
'pain cursing secretly' is the wordplay.
'secretly' indicates the answer is hidden within the clue.
'INCUR' can be found hidden inside 'pain cursing'.
(Other definitions for incur that I've seen before include "Meet" , "Fall into - invite" , "Become subject to (eg, taxes)" , "Become responsible for" , "Attract" .)