Janus-faced

from WordNet (r) 3.0 (2006)

Janus-faced
    adj 1: having or concerned with polarities or contrasts; "a
           Janus-faced view of history"; "a Janus-faced policy"
    2: marked by deliberate deceptiveness especially by pretending
       one set of feelings and acting under the influence of
       another; "she was a deceitful scheming little thing"- Israel
       Zangwill; "a double-dealing double agent"; "a double-faced
       infernal traitor and schemer"- W.M.Thackeray [syn:
       {ambidextrous}, {deceitful}, {double-dealing}, {duplicitous},
       {Janus-faced}, {two-faced}, {double-faced}, {double-tongued}]
    3: having two faces--one looking to the future and one to the
       past; "Janus the two-faced god" [syn: {Janus-faced}, {two-
       faced}]

from The Collaborative International Dictionary of English v.0.48

Janus-faced \Ja"nus-faced`\, a.
   Double-faced; deceitful.
   [1913 Webster]

   {Janus-faced lock}, one having duplicate faces so as to go
      upon a right or a left hand door, the key entering on
      either side indifferently. --Knight.
      [1913 Webster]