Meaning

noun a young dog

noun an inexperienced young person

originFrom earlier puppie (“a woman's pet dog”), of uncertain origin, but probably from Middle English *puppee, *poupee, from Old French poupée, popée (“a doll; puppet”). More at puppet. Mostly displaced native Middle English whelp (“puppy”), from Old English hwelp, whence Modern English whelp and whelpie.

Etymology from Wiktionary, CC BY-SA 3.0