In Vedānta and modern Hindu teaching, self-realisation means knowing oneself as ātman, one with Brahman, not as a belief but as lived fact. Ramana Maharshi taught that it is not the attainment of something new but the removal of the false idea that one is not already the Self.
Self-Realisation
The direct knowledge of one’s true nature as the Self, beyond body and mind.
Also: self-realization, atma-jnana