shrewd

The story

1. Old English · inherited fromsċrēawa“wicked person”
2. Middle English · inherited fromschrewed“depraved; wicked”
3. English todayshrewd

From Middle English schrewed (“depraved; wicked”, literally “accursed”), from schrewen (“to curse; beshrew”), from schrewe, schrowe, screwe (“evil or wicked person/thing”), from Old English sċrēawa (“wicked person”, literally “biter”). Equivalent to shrew + -ed. More at shrew. The sense of "cunning" developed in early 16ᵗʰ c., gradually gaining a positive connotation by 17ᵗʰ c.