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):

deviously
    adv 1: in a devious manner; "he got the promotion by behaving
           deviously"