c. 1300, "bondsman; common man, man of low birth," from Old Norse karl "man (as opposed to "woman"), male, freeman," from Proto-Germanic *karlon- (source also of Dutch karel "a fellow," Old High German karl "a man, husband), the same base that produced Old English ceorl "man of low degree" (see churl) and the masc. proper name Carl.
The Mellere was a stout carle for the nones [Chaucer]
"outgoing, overtly expressive person," 1916, extravert (spelled with -o- after 1918, by influence of introvert), from German Extravert, from extra "outside" (see extra-) + Latin vertere "to turn" (from PIE root *wer- (2) "to turn, bend"). Used (with introvert) in English by doctors and scientists in various literal senses since 1600s, but popularized in a psychological sense early 20c. by Carl Jung. Related: Extroverted.
1650s, "a whole comprised of interconnected parts," from complex (adj.). Latin completus as a noun meant "a surrounding, embracing, connection, relation." Psychological sense of "connected group of repressed ideas" was established by C.G. Jung, 1907.