The Collaborative International Dictionary of English v.0.48:

Puny \Pu"ny\, a. [Compar. Punier; superl. Puniest.] [F.
   pu[^i]t['e] younger, later born, OF. puisn['e]; puis
   afterwards (L. post; see Post-) + n['e] born, L. natus. See
   Natal, and cf. Puisne.]
   Imperfectly developed in size or vigor; small and feeble;
   inferior; petty.
   [1913 Webster]

         A puny subject strikes at thy great glory. --Shak.
   [1913 Webster]

         Breezes laugh to scorn our puny speed.   --Keble.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Puny \Pu"ny\, n.
   A youth; a novice. [R.] --Fuller.
   [1913 Webster]

WordNet (r) 3.0 (2006):

puny
    adj 1: inferior in strength or significance; "a puny physique";
           "puny excuses"
    2: (used especially of persons) of inferior size [syn: puny,
       runty, shrimpy]

Moby Thesaurus II by Grady Ward, 1.0:

154 Moby Thesaurus words for "puny":
   Lenten, Spartan, abstemious, ascetic, attenuated, austere,
   breakable, brittle, cadaverous, cheap-jack, cobwebby, corpselike,
   cramped, crumbly, dainty, decrepit, delicate, delicately weak,
   diminutive, dinky, dwarf, dwarfed, dwarfish, effeminate,
   emacerated, emaciate, emaciated, exiguous, feeble, flimsy, fragile,
   frail, frangible, frugal, gimcrack, gimcracky, gossamery, haggard,
   half-pint, hollow-eyed, impoverished, inconsequential, inferior,
   infirm, insignificant, jejune, jerkwater, jerry, jerry-built,
   knee-high, lean, light, lightweight, limited, little, marantic,
   marasmic, meager, mean, measly, midget, minor, minute, miserly,
   namby-pamby, narrow, negligible, niggardly, niggling, nugatory,
   one-horse, paltry, papery, parsimonious, pasteboardy, peaked,
   peaky, petite, pettifogging, petty, picayune, picayunish, piddling,
   piffling, pinched, pindling, pint-sized, poky, poor, punk, pygmy,
   scant, scanty, scrawny, scrimp, scrimpy, shattery, short,
   shriveled, sickly, sissified, skeletal, skimp, skimpy, sleazy,
   slender, slight, slim, small, small-beer, small-time, smallish,
   spare, sparing, starvation, starved, starveling, stingy, stinted,
   straitened, stunted, subsistence, tabetic, tabid, tacky, thin,
   tinhorn, tiny, trifling, trivial, two-bit, two-by-four,
   underdeveloped, underfed, undernourished, undersized, unimportant,
   unnourishing, unnutritious, unsound, unsubstantial, useless,
   wasted, watered, watery, weak, weakly, weazeny, wispy, withered,
   wizened, womanish, worthless, wraithlike