Skinflint regularly emails heirs (5)
I believe the answer is:
miser
'skinflint' is the definition.
(synonyms)
'regularly emails heirs' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'emails'+'heirs'='emailsheirs'
The alternate letters of 'emailsheirs' are 'MISER'.
(Other definitions for miser that I've seen before include "auger" , "Pinchpenny" , "not a spendthrift" , "Ungenerous hoarder" , "Person who hoards money" .)