A Theosophical definition of Yogi :

Yogi

(Yogin, Sanskrit) A yogi is a devotee, one who practices the Yoga system or one or more of its various subordinate branches.

In some cases, yogis are those who strive in various ways to conquer the body and physical temptations, for instance by torture of the body. They also study more or less some of the magnificent philosophical teachings of India coming down from far distant ages of the past; but mere mental study will not make a man a mahatma, nor will any torture of the body bring about the spiritual vision  - the vision sublime. (See also Yoga)

See also: Yogi, Mysticism, Body Mind and Soul)

yogi:

yogi. One who practices yoga.

(See also: yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Yogi:

Yogi. One who has mastered himself and controls his senses.

(See also: Yogi, Tantra, Tantra Dictionary, Body Mind and Soul)

Yogi: one who practices yoga

(See also: Yogi, Hinduism, Yoga, Sanskrit Dictionary, Body Mind and Soul)

Yogi: practitioner of yoga

(See also: Yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Yogi: Literally, one who practices Yoga. In common usage it refers to one who has mastered the practice of yoga, and teaches it to others.

(See also: Yogi, Yoga, Yoga Dictionary)

YOGI(N): one who practises Yoga; one who is established in Yoga

(See also: YOGI, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Yogi: One who practises Yoga; one who strives earnestly for union with God; an aspirant going through any course of spiritual discipline.

(See also: Yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Yogi:

1)  One who practices yoga.

2)  One who has attained perfection through yogic practices.

(See also: Yogi, Yoga, Yoga Dictionary, Siddha Yoga, Siddha Yoga Dictionary)

Yogi:

One who practices yoga; also, one who has attained perfection through yogic practices.

(See also: Yogi, Kundalini, Kundalini Yoga, Kundalini Dictionary)

Yogi (Sanskrit).

(1) Not "a state of six-fold bodily and mental happiness as the result, of ecstatic meditation" (Eitel) but a state which, when reached, makes the practitioner thereof absolute master of his six principles", he now being merged in the seventh. It gives him full control, owing to his knowledge of SELF and Self, over his bodily, intellectual and mental states, which, unable any longer to interfere with, or act upon, his Higher Ego, leave it free to exist in its original, pure, and divine state.

(2) Also the name of the devotee who practises Yoga.

(See also: Yogi, Theosophy, Spirituality, Body mind and Soul, Spiritual Dictionary, )

Yogi:

Yogi (n): one who practices yoga; one who is  established in yoga.

(See also: Yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

jnana-yogi:

jnana-yogi (jnaana-yogi). Yogi on the path of spiritual wisdom.

(See also: jnana-yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

siddha yogi: (Sanskrit) "Yogi of perfection." A perfected one, adept, a realized being who is the embodiment of the most profound yogic states and has attained magical or mystical powers.

See: siddha yoga, siddhi.

(See also: Siddha yogi, Hinduism, Body Mind and Soul)

PURNA-YOGI: A full-blown yogi.

(See also: PURNA-YOGI, Yoga, Yoga Dictionary)

raja-yogi:

raja-yogi (raaja-yogi). Yogi on the path of royal yoga (raja-yoga).

(See also: raja-yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Bhakti Yogi: One who practices Bhakti Yoga.

(See also: Bhakti Yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

bhakthi-yogi:

bhakthi-yogi. Yogi on the path of devotion.

(See also: bhakthi-yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

karma-yogi:

karma-yogi. Yogi who dedicates his actions to God.

(See also: karma-yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

Purna-Yogi:

Purna-Yogi: a full-blown yogi.

(See also: Purna-Yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

karma yogi:

person who is selflessly devoted to work

(See also: karma yogi, Hinduism, Hinduism Dictionary, Sanskrit Dictionary, Body Mind and Soul)

YOGI (N): One who practices Yoga; one who is established in Yoga.

(See also: YOGI (N, Yoga, Yoga Dictionary)