Chink

google

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mid 16th century: related to chine2.

wiktionary

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Of uncertain origin; but apparently an extension (with formative -k) of Middle English chine, from Old English ċine(“a crack, chine, chink”), equivalent to chine +‎ -k.

Alternatively, the -k may represent an earlier unrecorded diminutive, perhaps from Middle English *chinek, making it equivalent to chine +‎ -ock(diminutive ending).

Onomatopoeic.

chink (plural chinks)

chink (plural chinks)

etymonline

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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," from Proto-Germanic *kino-(source also of 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.2)

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

chink (n.3)

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