ничтожество

1) General subject: O, blighter, cipher, crum, crumb bum, drongo, duffer, gink, half pint, insignificant being, jack sprat, jack-straw, jack-straws, jackstraw, lay figure, lay-figure (о человеке), losel, naething, nebbish, negligible quantity, nobody, nonentity (о человеке), nothingness, nought (о человеке), nullity (о человеке), ought (о человеке), picayune, pigmy, pipsqueak, piss ant, poor stick, pygmy, rip, schlep, shrimp, snipe, vanity, whiffler, zero (о человеке), no-goodnik, naught, crum-bum, twerp, third-rater, loser

2) Colloquial: nitwit, pathetic

3) Dialect: snipper-snapper

4) American: cheap skate, jerk, schlepp, whiffet

5) Literal: insect

6) Rare: nihil

7) Mathematics: cypher

8) Australian slang: also-ran, bottle-oh's rouseabout, skunk

9) Scornful: Lilliputian (о человеке), Tom Thumb, pismire, whippersnapper, whipster

10) Jargon: dipshit, dot, half-pint, hoddy-doddy, nit, patsy, piss-ant, schloomp, schlump, squeegie, squegee, waste of life (e.g. Dude, do something and stop being a waste of life!), zerk, muff cabbage/ muff garbage (http://www.urbandictionary.com/define.php?term=Muff%20Cabbage&defid=5279477), Kilroy, pea soup, schlub

11) Simple: small potatoes