Rishi [Hindi/Sanskrit:ऋषि] is an ascetic, who is devoted to religious activities. He is devoted to religious activities. In ancient times Kings were guided by Rishis as Raaj Dharma was also considered a part of Dharma. Rishi spent most of their life in forest. They were renounced persons. They were respected due to there knowledge of Dharma and there selflessness life.
Muni [Hindi/ Sankrit: मुनि] word is somewhat related to Rishi. A Rishi who performs devotion by keeping himself silent is called a Muni. Actually this is normally pronunced with Rushi as Rishi-Muni (ऋषि मुनि). Different types of Rishis are mentioned in the Sanatan (Hindu Religious) literarure.