erudite adj.

word-forming element, in English meaning usually "out of, from," but also "upwards, completely, deprive of, without," and "former;" from Latin ex "out of, from within; from which time, since; according to; in regard to," from PIE *eghs "out" (source also of Gaulish ex-, Old Irish ess-, Old Church Slavonic izu, Russian iz). In some cases also from Greek cognate ex, ek. PIE *eghs had comparative form *eks-tero and superlative *eks-t(e)r-emo-. Often reduced to e- before -b-, -d-, -g-, consonantal -i-, -l-, -m-, -n-, -v- (as in elude, emerge, evaporate, etc.).

late 13c., "coarse, rough, without finish" (of surfaces), from Old French ruide (13c.) and directly from Latin rudis "rough, crude, unlearned," a word of uncertain etymology, related to rudus "rubble." The usual preferred derivation is that it is from the same source as Latin rufus "red" (see rufous) via a notion of raw ("red") meat, but de Vaan points out "there is not a shimmer of a meaning 'red' in rudis or in rudus 'rubble', so that the supposed shift from 'crude (meat)' > 'crude' rests in the air."

The senses of "ill-mannered, uncultured, boorish; uneducated, ignorant" are from mid-14c.; also of actions or acts, "violent, rough." That of "of low birth or position, common, humble" is from late 14c. The meaning "marked by incivility, contrary to the requirements of courtesy" is perhaps late 14c., certainly by 16c., but difficult to distinguish from earlier "unrefined, uncultured" senses.

Rude boy (also Rudie, for short) in Jamaican slang is attested from 1967. Figurative phrase rude awakening is attested from 1895.

c. 1400, "instruction, education," from Latin eruditionem (nominative eruditio) "an instructing, instruction, learning," noun of action from past participle stem of erudire "to educate, instruct, polish" (see erudite). Meaning "learning, scholarship" is from 1520s.