Looking for a Very Specific Adjective

Perhaps guileful or Machiavellian.

guileful (from Wiktionary, 2019):

Full of guile; treacherously deceptive.

with guile being (from Wiktionary, 2019):

Astuteness often marked by a certain sense of cunning or artful deception.


Machiavellian (from Wiktionary, 2019):

Attempting to achieve goals by cunning, scheming, and unscrupulous methods, especially in politics or in advancing one's career.