peek (v.) Look up peek at Dictionary.com
late 14c., piken "look quickly and slyly," of unknown origin. The words peek, keek, and peep all were used with more or less the same meaning 14c.-15c.; perhaps the ultimate source was Middle Dutch kieken. Related: Peeked; peeking.
peek (n.) Look up peek at Dictionary.com
"a peek, glance," 1844, from peek (v.).