YOGI, a Hindu religious ascetic. The word yoga means union, and first occurs in the later Upanishads; and yogi means one who practises yoga, with the object of uniting his soul with the divine spirit. This union, when accomplished by the individual soul, must enhance its susceptibilities and powers, and so the yogis claim a far-reaching knowledge of the secrets of nature and extensive sway over men and natural phenomena. The most usual manifestation of this power is a state of ecstasy, of the nature of self-hypnotism.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)