Overview
In Indian religions, a rishi (Sanskrit: ऋषि, IAST: ṛṣi) is an accomplished and enlightened person. Rishis are mentioned across various Vedic texts and are traditionally believed to have composed the hymns of the Vedas.
The post-Vedic tradition of Hinduism regards rishis as "great yogis" or "sages" who, through intense meditation (tapas), realised the supreme truth and eternal knowledge. This realised wisdom is held to have been expressed by them in the form of hymns, which were subsequently preserved within the Vedic corpus.
The concept also extends beyond Hinduism into other Indian traditions. In Pali literature associated with Buddhism, the term appears as Isi. Within the Buddhist usage, the designation may apply to Buddhas, Paccekabuddhas, Arahats, or a monk of high rank, reflecting the broader Indic understanding of the rishi as a figure of spiritual attainment.
References
Adapted from the English Wikipedia article on Rishi.