Adjectives

(s)astute, sharp, shrewdmarked by practical hardheaded intelligence“a smart businessman”, “an astute tenant always reads the small print in a lease”, “he was too shrewd to go along with them on a road that could lead only to their overthrow”
(s)calculating, calculative, conniving, scheming, shrewdacting with a specific goal“the most calculating and selfish men in the community”