peeper

noun

1. a person or thing that emits or utters a peeping sound.
2. Northeastern U.S. any of several frogs having a peeping call, especially the spring peeper.

noun

1. a person who peeps in an abnormally prying manner; a voyeur.
2. peepers, Slang. the eyes.

noun

1. a person who peeps
2. (often plural) a slang word for eye 1 (def. 1)

n.1650s, “one who peeps,” agent noun from peep (v.1). Slang meaning “eye” is c.1700. From 1590s as “young chicken” and 1857 as “tree frog” (American English), both from peep (v.2).