The Collaborative International Dictionary of English v.0.48:

Slinky \Slink"y\, a.
   Thin; lank. [Prov. Eng. & U. S.]
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "slinky":
   airy, attenuate, attenuated, back-door, backstairs, boyish,
   clandestine, covert, cowering, cringing, delicate, diaphanous,
   diluted, ethereal, feline, fine, fine-drawn, finespun, flimsy,
   frail, furtive, gauzy, girlish, gossamer, gracile, hidlings,
   hole-and-corner, hugger-mugger, insubstantial, lacy, light, misty,
   papery, privy, quailing, quiet, rare, rarefied, shifty, skulking,
   slender, slenderish, slight, slight-made, slim, slimmish, slinking,
   sly, small, sneaking, sneaky, stealthy, subtle, surreptitious,
   svelte, sylphlike, tenuous, thin, thin-bodied, thin-set, thin-spun,
   thinnish, threadlike, under-the-counter, under-the-table,
   undercover, underground, underhand, underhanded, unobtrusive,
   vague, wasp-waisted, watered, watered-down, watery, weak, willowy,
   wiredrawn, wispy