pur-

c. 1300, pur blind "entirely blind," as a noun, "a blind person," later "partially blind, blind in one eye" (late 14c.), the main modern sense, from blind (adj.) + pur "entirely, completely, absolutely."

The adverb forming the first element is from an identical Middle English adjective pur "unadulterated, unmixed" (c. 1300), usually explained as from Old French pur and Latin purus (see pure). It might have been influenced by the Anglo-French perfective prefix pur- (see pur-). The sense of "dull" is recorded from 1530s.

c. 1300, purchasen, "acquire, obtain; get, receive; procure, provide," also "accomplish or bring about; instigate; cause, contrive, plot; recruit, hire," from Anglo-French purchaser "go after," Old French porchacier "search for, procure; purchase; aim at, strive for, pursue eagerly" (11c., Modern French pourchasser), from pur- "forth" (possibly used here as an intensive prefix; see pur-) + Old French chacier "to run after, hunt, chase" (see chase (v.)).

Originally to obtain or receive as due in any way, including through merit or suffering; the specific sense of "acquire or secure by expenditure of money or its equivalent, pay money for, buy" is attested from mid-14c., though the word continued to be used for "to get by conquest in war, obtain as booty" up to 17c. Related: Purchased; purchasing.