Coy

Chamber's Etymological of the English Language · 1895 · p. 112

koy, adj. modest bashful shy adv. — Coyly. n. Coy'ne . [Fr. coi from L quietus quiet.] [ishly —n. Coy'ishno . — Coylsh, koy'ish, adj somewhat coy. adv. Coy'-