"small show consisting of pictures viewed through a hole fitted with a magnifying glass," 1813, originally an entertainment for children (not typically salacious until c. 1914), from peep (v.1) + show (n.).
"to glance, look from a state of concealment" (especially through or as through a small or narrow opening), mid-15c., pepen, perhaps an alteration of Middle English piken (see peek (v.)). Hence, "to come partially into view, begin to appear" (1530s). Peeping Tom "a curious prying fellow" [Grose] is from 1796 (see Godiva).
c. 1300, "act of exhibiting to view," from show (v.). Sense of "appearance put on with intention to deceive" is recorded from 1520s. Meaning "display, spectacle" is first recorded 1560s; that of "ostentatious display" is from 1713 (showy is from 1712). Sense of "entertainment program on radio or TV" is first recorded 1932. Meaning "third place in a horse race" is from 1925, American English (see the verb).
Show of hands is attested from 1789; Phrase for show "for appearance's sake" is from c. 1700. Show business is attested from 1850; shortened form show biz used in Billboard magazine from 1942. Actor's creed the show must go on is attested from 1890. Show-stopper is from 1926; show trial is attested by 1937.
<a href="https://www.etymonline.com/word/peep-show">Etymology of peep-show by etymonline</a>
Harper, D. (n.d.). Etymology of peep-show. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/peep-show