shrewd

(s) marked 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
astute, sharp,
(s) used of persons
- the most calculating and selfish men in the community
calculating, calculative, scheming, conniving,

astute sharp calculating calculative scheming conniving

shred shrew

shrewdly shrewdness