精明的
敏锐的
狡猾的（shrewd的最高级）

Shrewd \Shrewd\, a. [Compar. {Shrewder}; superl. {Shrewdest}.]
[Originally the p. p. of shrew, v.t.]
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.
※ -- {Shrewd"ly}, adv. -- {Shrewd"ness},
n.