conniving

(verb) encourage or assent to illegally or criminally. Synonyms: connive.

(verb) form intrigues (for) in an underhand manner. Synonyms: scheme, intrigue, connive.

(adj) acting together in secret toward a fraudulent or illegal end. Synonyms: collusive.

(adj) used of persons. Synonyms: calculating, calculative, scheming, shrewd. Example: "The most calculating and selfish men in the community."