Purblind means half blind, or slow to see the point. Purblind old fool, purblind to the danger, a purblind policy.
The figurative sense is the live one and it is always an accusation of wilful stupidity. The word once meant completely blind — the pur- is the same as pure, meaning utterly — and it weakened to mean partly blind, which is the reverse of what usually happens.
1adjectivepurblindHalf blind, or slow to see the point.
“The purblind old dog bumped into the door as it wandered around the house.”
purblind is a quality of blindness.
From pure plus blind, where pure meant utterly. The word first meant completely blind and weakened to partly blind.
Proto-Indo-European
*pewH- — to be clean; pure
Middle English
purblind — (adjective) completely blind; blind in one eye; near-sighted; (noun) near-sighted animal, specifically a hare
English, today
purblind
Built from
The adjective is derived from Middle English purblind (“(adjective) completely blind; blind in one eye; near-sighted; (noun) near-sighted animal, specifically a hare”)poreblind, pore blynde, pur blind, purblinde, purblynd, purblynde, purblyynd, pure blynde, possibly from pur, pure (“completely, entirely”) (ultimately from Proto-Indo-European pewH- (“to be clean; pure”); influenced by pur-) + blind (“sightless, blind”) (ultimately from Proto-Indo-European bʰlendʰ- (“to blend, mix up; to make cloudy or opaque”)). completely (“completely blind”) was the original sense. The senses denoting partial blindness are possibly the result of confusion of the first element pur- with poor, perhaps through folk etymology. (Compare parboil#Etymology regarding per versus pars.) The noun and verb are derived from the adjective.
Etymology from Wiktionary, CC BY-SA