The Collaborative International Dictionary of English v.0.48:

Shifty \Shift"y\, a.
   Full of, or ready with, shifts; fertile in expedients or
   contrivance. --Wright.
   [1913 Webster]

         Shifty and thrifty as old Greek or modern Scot, there
         were few things he could not invent, and perhaps
         nothing he could not endure.             --C. Kingsley.
   [1913 Webster] Shiite

WordNet (r) 3.0 (2006):

shifty
    adj 1: characterized by insincerity or deceit; evasive; "a
           devious character"; "shifty eyes" [syn: devious,
           shifty]
    2: changing position or direction; "he drifted into the shifting
       crowd"; "their nervous shifting glances"; "shifty winds"
       [syn: shifting, shifty]

Moby Thesaurus II by Grady Ward, 1.0:

235 Moby Thesaurus words for "shifty":
   Machiavellian, Machiavellic, acute, adrift, afloat, alternating,
   ambidextrous, amoral, amorphous, arch, artful, astute, back-door,
   backstairs, bent, cagey, calculating, canny, capricious,
   changeable, changeful, chiseling, clandestine, clever, close,
   closemouthed, collusive, conniving, conscienceless, conspiratorial,
   corrupt, corrupted, covert, covinous, crafty, criminal, crooked,
   cunning, cute, dangerous, dark, deceitful, deceiving, deep,
   deep-laid, designing, desultory, deviable, devious, diplomatic,
   discreet, dishonest, dishonorable, dizzy, dodging, double,
   double-dealing, doubtful, dubious, duplicitous, eccentric, elusive,
   elusory, equivocating, erratic, evasive, false, falsehearted,
   fast and loose, feline, felonious, fickle, finagling, fishy,
   fitful, flickering, flighty, flitting, fluctuating, foxy,
   fraudulent, freakish, furtive, giddy, guileful, hazardous,
   hidlings, hole-and-corner, hugger-mugger, ill-got, ill-gotten,
   immoral, impetuous, impulsive, inconsistent, inconstant,
   indecisive, indirect, infirm, ingenious, insecure, insidious,
   insubstantial, inventive, irregular, irresolute, irresponsible,
   knavish, knowing, lying, malingering, mazy, mendacious, mercurial,
   moody, not kosher, pawky, perfidious, perilous, politic,
   precarious, privy, provisional, questionable, quiet, rambling,
   ready, resourceful, restless, risky, roguish, rotten, roving,
   scatterbrained, scheming, secret, secretive, serpentine, shady,
   shaky, shameless, shapeless, sharp, shifting, shirking, shrewd,
   shuffling, sinister, skulking, slick, slinking, slinky, slippery,
   sly, smooth, snaky, sneaking, sneaky, sophistical, spasmodic,
   spineless, stealthy, strategic, subtile, subtle, supple,
   surreptitious, suspicious, tactical, temporary, tentative,
   ticklish, traitorous, treacherous, trickish, tricksy, tricky,
   two-faced, unaccountable, uncertain, uncommunicative,
   unconscienced, unconscientious, unconscionable, uncontrolled,
   undependable, under-the-counter, under-the-table, undercover,
   underground, underhand, underhanded, undisciplined, unethical,
   unfaithworthy, unfixed, unobtrusive, unpredictable, unprincipled,
   unreliable, unrestrained, unsavory, unscrupulous, unsettled,
   unsolid, unsound, unstable, unstable as water, unstaid,
   unsteadfast, unsteady, unstraightforward, unsubstantial, unsure,
   untrustworthy, untruthful, vacillating, vagrant, variable,
   vicissitudinary, vicissitudinous, volatile, vulpine, wandering,
   wanton, wary, wavering, wavery, wavy, wayward, whimsical, wily,
   wishy-washy, without remorse, without shame