ETYM Old Eng. piken: cf. French piquer to pierce, prick, Eng. pique. Related to Peak.
(Homonym: peak, pique).
1. To look furtively; SYN. peep.
2. To peer through a crack or hole or from a place of concealment — often used with in or out.
3. To take a brief look; glance.

1. To secretly collect sensitive or classified information; engage in espionage
2. To watch, observe, or inquire secretly; SYN. stag, snoop.