Inside the Universes

'duplicitous'

[ambidextrous.s.01] as in: marked by deliberate deceptiveness especially by pretending one set of feelings and acting under the influence of another; - Israel Zangwill; ; - W.M.Thackeray

Examples:
she was a deceitful scheming little thing
a double-dealing double agent
a double-faced infernal traitor and schemer