Meaning of Janus-faced

(adj) having or concerned with polarities or contrasts; "a Janus-faced view of history"; "a Janus-faced policy"

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

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