What is "shrewdest"

Shrewd \Shrewd\, a. [Compar. Shrewder; superl. Shrewdest.]

1. Inclining to shrew; disposing to curse or scold; hence, vicious; malicious; evil; wicked; mischievous; vexatious; rough; unfair; shrewish. [Obs.]
   --Chaucer.

   [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.

   Syn: Keen; critical; subtle; artful; astute; sagacious; discerning; acute; penetrating.

   Usage: Shrewd, Sagacious. One who is shrewd is keen to detect errors, to penetrate disguises, to foresee and guard against the selfishness of others. Shrewd is a word of less dignity than sagacious, which implies a comprehensive as well as penetrating mind, whereas shrewd does not. [1913 Webster] -- Shrewd"ly, adv. -- Shrewd"ness, n.

a. (en-superlative of: shrewd)