A long time back I have read in one of the website that, a Rasool or a Messenger(Peace be upon them) is one who brings new Deen to the people, and a Prophet or a Nabi(Peace be upon them) is one who guides the people in following that Deen.
This is the most preferred view that a Rasul is one who brings a new law,
and a Nabi is one who guides according to the previously revealed law.
and Allah Ta’ala Knows Best
Moulana Imraan Vawda
for: FATWA DEPT.