Chink (n.2)

"a Chinese person," 1901, derogatory, perhaps derived somehow from China, or else from chink (n.1) with reference to eye shape.

chink (n.1)

"a split, crack," 1530s, with unetymological -k + Middle English chine (and replacing this word) "fissure, narrow valley," from Old English cinu, cine "fissure," which is related to cinan "to crack, split, gape," a common Germanic word (compare Old Saxon and Old High German kinan, Gothic uskeinan, German keimen "to germinate;" Middle Dutch kene, Old Saxon kin, German Keim "germ"). The connection being in the notion of bursting open.

chink (n.3)

"sharp, clear, metallic sound" (especially of coin), 1580s, probably imitative. As a verb from 1580s. Related: Chinked; chinking.