1540s, "having life, not dead," a shortening of alive (q.v.). From 1610s of fire, coal, etc., "burning, glowing;" 1640s of things, conditions, etc., "full of active power;" sense of "containing unspent energy or power" (live ammunition) is from 1799.

Meaning "in-person, not recorded" (of performance) is attested by 1917. Live wire is attested from 1890, "circuit through which an electric current is flowing;" figurative sense of "active person" is from 1903. Jocular real live "genuine" is from 1887. The older adjective is lively.

A GRIM RECORD — The death harvest of the "live wire" and "third rail" goes right on. It is not governed by seasons nor, qualified by time. It is the ubiquitous epidemic of electricity, defiant of doctors and ruthless as fate. [The Insurance Press, Aug. 22, 1900]

"one who avoids company," 1946; see lone. Apparently first in U.S. baseball slang:

Ted [Williams] is likable enough in spite of his obsession with his specialty. He is something of a "loner," and he refuses to pal around with his teammates in off hours, but in the clubhouse he does his share of the talking. [Life magazine, Sept. 23, 1946]

"drearily solitary; secluded from society; dejected from want of company," 1640s, from lone (adj.) + -some (1). Related: Lonesomeness. An older adjective was loneful (1560s).

Loneliness expresses the uncomfortable feelings, the longing for society, of one who is alone. Lonesomeness may be a lighter kind of loneliness, especially a feeling less spiritual than physical, growing out of the animal instinct for society and the desire of protection, the consciousness of being alone .... Lonesomeness, more often than loneliness, may express the impression made upon the observer. [Century Dictionary]