The Collaborative International Dictionary of English v.0.48:

Devious \De"vi*ous\, a. [L. devius; de + via way. See
   Viaduct.]
   1. Out of a straight line; winding; varying from directness;
      as, a devious path or way.
      [1913 Webster]

   2. Going out of the right or common course; going astray;
      erring; wandering; as, a devious step.

   Syn: Wandering; roving; rambling; vagrant. -- De"vi*ous*ly,
        adv. -- De"vi*ous*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

devious
    adj 1: indirect in departing from the accepted or proper way;
           misleading; "used devious means to achieve success";
           "gave oblique answers to direct questions"; "oblique
           political maneuvers" [syn: devious, oblique]
    2: characterized by insincerity or deceit; evasive; "a devious
       character"; "shifty eyes" [syn: devious, shifty]
    3: deviating from a straight course; "a scenic but devious
       route"; "a long and circuitous journey by train and boat"; "a
       roundabout route avoided rush-hour traffic" [syn: devious,
       circuitous, roundabout]

Moby Thesaurus II by Grady Ward, 1.0:

172 Moby Thesaurus words for "devious":
   Byzantine, O-shaped, aberrant, aberrative, ambagious, amoral,
   anfractuous, artful, backhand, backhanded, balled up, bending,
   calculating, canny, circuitous, circular, complex, complicated,
   confounded, confused, conscienceless, convoluted, corrupt,
   corrupted, crabbed, crafty, criminal, crooked, cunning, curving,
   daedal, dark, deceitful, deceptive, deflectional, departing,
   designing, desultory, deviant, deviating, deviative, deviatory,
   digressive, discursive, dishonest, dishonorable, divagational,
   divergent, diverting, double-dealing, doubtful, dubious,
   duplicitous, elaborate, embrangled, entangled, errant, erratic,
   erring, evasive, excursive, felonious, fishy, fouled up, foxy,
   fraudulent, furtive, guileful, helical, ill-got, ill-gotten,
   immoral, implicated, indirect, insidious, insincere, intricate,
   involuted, involved, knotted, knowing, labyrinthian, labyrinthine,
   left-handed, lonesome, loused up, many-faceted, matted, mazy,
   meandering, messed up, misleading, mixed up, mucked up,
   multifarious, not kosher, oblique, orbital, out-of-the-way, pawky,
   perplexed, planetary, plotting, questionable, rambling, ramified,
   remote, removed, retired, rotary, rotten, round, roundabout,
   roving, scheming, screwed up, secret, secretive, serpentine, shady,
   shameless, shifting, shifty, shrewd, side, sidelong, sinister,
   sinistral, sinuous, slick, slippery, sly, smooth, snaky, snarled,
   sneaking, sneaky, spiral, stray, subtile, subtle, surreptitious,
   suspicious, swerving, tangled, tangly, tortuous, treacherous,
   tricky, turning, twisted, twisting, unconscienced, unconscientious,
   unconscionable, underhand, underhanded, undirected, unethical,
   unprincipled, unsavory, unscrupulous, unstraightforward, vagrant,
   veering, vulpine, wandering, wily, winding, without remorse,
   without shame, zigzag