questions

[Chelluri Nageswar Rao]

                                                   Matrenamah
Namaste!

Could somebody answer following two questions

1. What is the difference between "Muni" and "Rishi"
Markandeya is reffered to as "MahaMuni"
Ramana ..........................   "MahaRishi"

2. In one of the shanti mantras it says "SWASTHINO BRIHASPATI DADHATU"
I don't know much sanskrit but I know that Dadhatu means to "gives"
What is "Swasthino" means?

Regards
                                                                        Rao