1680s, thieves' cant, a compound of kid (n.) "child" and nap (v.) "snatch away," which probably is a variant of nab (v.). Perhaps a back-formation from kidnapper, which is recorded earlier. Originally "to steal children to provide servants and laborers in the American colonies." Related: Kidnapped; kidnapping.

"playful teaser," 1888, agent noun from kid (v.).

by 1893, familiar form of kid (n.) in the "child" sense + slang suffix -o (q.v.).

also kiddie; 1570s as "young goat;" 1780 as "flash thief;" 1889 as "little child," from various senses of kid (n.) + -y (3). Other diminutives in the "small child" sense were kidlet (1889), kidling (1899). Related: Kiddies.