The Collaborative International Dictionary of English v.0.48:

Scrawny \Scraw"ny\ (skr[add]"n[y^]), a. [Cf. Scrannel.]
   Meager; thin; rawboned; bony; scranny.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scrawny
    adj 1: being very thin; "a child with skinny freckled legs"; "a
           long scrawny neck" [syn: scraggy, boney, scrawny,
           skinny, underweight, weedy]
    2: inferior in size or quality; "scrawny cattle"; "scrubby cut-
       over pine"; "old stunted thorn trees" [syn: scrawny,
       scrubby, stunted]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "scrawny":
   Lenten, Spartan, abstemious, angular, anorectic, anorexic, ascetic,
   austere, bony, cadaverous, drawn, dwarfed, dwarfish, emaciated,
   exiguous, flat, flat-chested, fleshless, frugal, gangling, gangly,
   gaunt, gawky, haggard, impoverished, jejune, lank, lanky, lean,
   lean-fleshed, lean-looking, limited, meager, mean, miserly, narrow,
   niggardly, paltry, parsimonious, poor, puny, rawboned, reedy,
   scant, scanty, scraggy, scrimp, scrimpy, skeletal, skimp, skimpy,
   skinny, slender, slight, slim, small, spare, sparing, spidery,
   spindling, spindly, starvation, stingy, stinted, straitened,
   stunted, subsistence, thin, thin-bellied, thin-fleshed, twiggy,
   undersized, underweight, unnourishing, unnutritious, watered,
   watery