THESAURUS
whippersnapper
JD, a nobody, a nothing, boldface, brat, brazenface, chutzpanik, cipher, common man, dummy, elf, enfant terrible, figurehead, gamin, holy terror, hussy, imp, insignificancy, jackstraw, juvenile delinquent, lightweight, little fellow, little guy, little monkey, malapert, man of straw, mediocrity, minx, nebbish, nobody, nobody one knows, nonentity, nothing, nullity, obscurity, pip-squeak, puck, punk, punk kid, pup, puppy, runt, saucebox, scrub, shrimp, small fry, small potato, small potatoes, smart aleck, smart-ass, smarty, smarty-pants, spoiled brat, squirt, squit, swaggerer, upstart, urchin, whiffet, wise guy, wise-ass, zero, zilch
ROGET THESAURUS
whippersnapper
Infant
N
infant, babe, baby, babe in arms, nurseling, suckling, yearling, weanling, papoose, bambino, kid, vagitus, child, bairn, little one, brat, chit, pickaninny, urchin, bantling, bratling, elf, youth, boy, lad, stripling, youngster, youngun, younker, callant, whipster,
whippersnapper, whiffet, schoolboy, hobbledehoy, hopeful, cadet, minor, master, scion, sap, seedling, tendril, olive branch, nestling, chicken, larva, chrysalis, tadpole, whelp, cub, pullet, fry, callow, codlin, codling, foetus, calf, colt, pup, foal, kitten, lamb, lambkin, aurelia, caterpillar, cocoon, nymph, nympha, orphan, pupa, staddle, girl, lass, lassie, wench, miss, damsel, demoiselle, maid, maiden, virgin, hoyden, infantine, infantile, puerile, boyish, girlish, childish, babyish, kittenish, baby, newborn, unfledged, new-fledged, callow, in the cradle, in swaddling clothes, in long clothes, in arms, in leading strings, at the breast, in one's teens.