two-faced

Adjective

• having two faces--one looking to the future and one to the past
  • Janus the two-faced god
    

• 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
    

Related words

• Synonyms: 
  Janus-faced , ambidextrous , deceitful , double-dealing , duplicitous , double-faced , double-tongued