Puny
mid 16th century (as a noun denoting a younger or more junior person): phonetic spelling of puisne.
wiktionary
A respelling of puisne, [1] from Anglo-Norman puisné(“later, more recent; junior; weakly”)[and other forms] and Middle French puisné(“born after (a specified person); younger, youngest; one who is born after (a specified person)”) (modern French puîné(“cadet (born after a sibling); a cadet (someone born after a sibling)”)), from puis(“after; since”) + né(“born”). [2]Puis is derived from Old French pois(“after; since”), from Vulgar Latin *postius(“afterward”), from Latin posteā(“afterwards; hereafter; thereafter; next, then”), from post(“after; since”) (ultimately from Proto-Indo-European *pós(“afterwards”)) + ea(“these (things)”); and né from Latin nātus(“born”), ultimately from Proto-Indo-European *ǵenh₁-(“to beget; to give birth; to produce”).
etymonline
puny (adj.)
1570s, "inferior in rank" (1540s as a noun, "junior pupil, freshman"), senses now obsolete, from French puisné (Modern French puîné), from Old French puisne "born later, younger, youngest" (12c., contrasted with aisné "first-born").
This is from puis nez, from puis "afterward" (from Vulgar Latin *postius, from Latin postea "after this, hereafter," from post "after," see post-, + ea "there") + Old French né "born," from Latin natus, past participle of nasci "be born" (Old Latin gnasci; from PIE root *gene- "give birth, beget"). Compare puisne.
The sense of "small, weak, insignificant, imperfectly developed in size or strength" is recorded from 1590s. Related: Puniness.
