Shrewd

a.	1.	Inclining to shrew; disposing to curse or scold; hence, vicious; malicious; evil; wicked; mischievous; vexatious; rough; unfair; shrewish. [Egypt] hath many shrewd havens, because of the great rocks that ben strong and dangerous to pass by. - Sir J. Mandeville. Every of this happy number That have endured shrewd days and nights with us. - Shak.
	2.	Artful; wily; cunning; arch. These women are shrewd tempters with their tongues. - Shak.
	3.	Able or clever in practical affairs; sharp in business; astute; sharp-witted; sagacious; keen; as, a shrewd observer; a shrewd design; a shrewd reply. Professing to despise the ill opinion of mankind creates a shrewd suspicion that we have deserved it. - Secker.

Adj.	1.	shrewd - 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" Synonyms: astute, sharp
	2.	shrewd - used of persons; "the most calculating and selfish men in the community" Synonyms: calculating, calculative, scheming, conniving

Byzantine, Daedalian, Machiavellian, Machiavellic, acute, all-knowing, apperceptive, appercipient, apprehending, apprehensive, arch, aware, cagey, calculated, calculating, canny, cognizant, comprehending, conscious, cute, deceitful, deep, deep-laid, designing, devious, diplomatic, discerning, farsighted, feline, foresighted, heady, insidious, insightful, inventive, judicious, keen, knowing, knowledgeable, manipulative, mindful, omniscient, pawky, penetrating, perceptive, percipient, perspicacious, piercing, polite, politic, prehensile, probing, prudent, quick-witted, ready, resourceful, sagacious, sage, savvy, scheming, sensible, serpentine, sharp, shifty, slick, slippery, smart, smooth, snaky, sneaky, sophistical, strategic, subtile, subtle, supple, tactical, tidy, trickish, tricksy, understanding, vulpine, wary, wise