1670s, apparently a "jingling extension" [OED] of *whip-snapper "a cracker of whips," or perhaps an alteration of snipper-snapper (1580s). Compare also late 16c. whipperginnie, a term of abuse for a woman.
whippersnapper (plural whippersnappers)
- A young and cheeky or presumptuous person.
young, cheeky person