shrewd (adj.) Look up shrewd at Dictionary.com
c.1300, "wicked, evil," from shrewe "wicked man" (see shrew). Compare crabbed from crab (n.), dogged from dog (n.), wicked from witch (n.). The sense of "cunning" is first recorded 1510s. Related: Shrewdly; shrewdness. Strutt's "Sports and Pastimes of the People of England" (1801) has a shrewdness of apes for a company or group of them. Shrewdie "cunning person" is from 1916.