Shrewd comes from Middle English shrewed ('wicked, evil'), originally the past participle of shrewen ('to curse'), from shrewe ('a wicked person, a shrew'); the sense shifted from 'malicious' to 'cunning' and then 'astute'. The historical chain includes Middle English shrewe. Older glosses in the chain include "wicked, evil", "to curse", "a wicked person, a shrew", and "malicious", which help explain the semantic range of the modern word. Morphologically, shrewd is best read as borrowing, yielding an English adjective shaped by both form history and later usage. In current English it functions as an adjective, with the sense "having sharp practical judgment and astuteness". English derivatives include shrewdly and shrewdness; related forms include shrew. The result is an English adjective whose etymology preserves the older forms while supporting the word's specialized modern meaning.