shrewd (adj.)

• acute
• all-knowing
• apperceptive
• apprehensive
• arch
• artful
• astute
• aware
• cagey
• calculated
• calculating
• canny
• clever
• cognizant
• comprehending
• conscious
• crafty
• cunning
• cute
• deceitful
• deep
• deep-laid
• designing
• devious
• diplomatic
• discerning
• farsighted
• feline
• foresighted
• foxy
• guileful
• heady
• ingenious
• insidious
• insightful
• intelligent
• 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
• scheming
• sensible
• serpentine
• sharp
• shifty
• slick
• slippery
• sly
• smart
• smooth
• snaky
• sneaky
• sophistical
• stealthy
• strategic
• subtle
• supple
• tactical
• tidy
• tricksy
• tricky
• understanding
• vulpine
• wary
• wily
• wise