mid-14c., colrik, "bilious of temperament or complexion," from Old French colerique, from Late Latin cholericus, from Greek kholerikos, from Greek kholera "a type of disease characterized by diarrhea, supposedly caused by bile," from khole "gall, bile," so called for its color, related to khloazein "to be green," khloros "pale green, greenish-yellow," from PIE root *ghel- (2) "to shine," with derivatives denoting "green, yellow," and thus "bile, gall." Meaning "easily angered, hot-tempered" is from 1580s (from the supposed effect of excess choler); that of "pertaining to cholera" is from 1834.
