word-forming element common in words of French and Latin origin, meaning primarily "through," thus also "throughout; thoroughly; entirely, utterly," from Latin preposition per (see per (prep.)).

"liable to be wearied," 1650s, from defatigate (v.), 1550s, from Latin defatigatus, past participle of defatigare "to weary, tire out, exhaust with labor," from de "utterly, down, away" (see de-) + fatigare "to weary" (see fatigue (n.)). Also see indefatigable.

c. 1200, "straight down, right down, perpendicularly," from down (adv.) + -right. The meaning "thoroughly, completely, utterly," often merely emphatic, is attested from c. 1300. As an adjective, "complete, absolute," from 1560s. Old English had dunrihte "downwards." The inverted form right-down is attested 17c.

c. 1300, despeir, "hopelessness, total loss of hope," from Anglo-French despeir, Old French despoir, from desperer (see despair (v.)). The native word was wanhope.

Despair naturally destroys courage and stops all effort, but may produce a new kind of courage and fierce activity founded upon the sense that there is nothing worse to be feared. In this despair is akin to desperation, which is an active state and always tends to produce a furious struggle against adverse circumstances, even when the situation is utterly hopeless. [Century Dictionary, 1897]

early 15c., "destroy utterly," literally "pull up by the roots," from Latin eradicatus, past participle of eradicare "root out, extirpate, annihilate," from assimilated form of ex "out" (see ex-) + radix (genitive radicis) "root" (from PIE root *wrād- "branch, root"). Related: Eradicated; eradicating; eradicable. The native form of the same idea is in Middle English outrōten "to root (something) out, eradicate" (early 15c.).