Middle English redi, with adjectival suffix -i (as in busy, crafty, hungry, etc.) + Old English ræde, geræde "prepared, ready, suitably equipped;" of a horse, "ready for riding."
This is reconstructed to be from Proto-Germanic *(ga)raitha- "arranged" (source also of Old Frisian rede "ready," Middle Dutch gereit, Old High German reiti, Middle High German bereite, German bereit, Old Norse greiðr "ready, plain," Gothic garaiþs "ordered, arranged"), which is perhaps from PIE root *reidh- "to ride" (see ride (v.)).
Lengthened in Middle English by change of ending. Sense of "at hand, present, available" is late 12c. Of money, "immediately available," c. 1300, hence slang noun the ready "cash" (1680s). Phrase at the ready "in the position of a soldier's firearm after the command '(make) ready!'" is attested from 1837. As an adverb, c. 1300, "at hand." A ready-reckoner (1757) was a book of tabulated calculations of the sort used in ordinary business and housekeeping.
early 13c., redien, "to administer" (a sense now obsolete); c. 1300, "to take aim;" mid-14c., "to make (something) ready, prepare, put into proper condition or order," from ready (adj.). "Somewhat rare between the 15th and 19th c." [OED]. Related: Readied; readying. Compare Dutch reeden "prepare, dress; German bereiten, Danish berede "prepare, get ready;" also compare redd (v.).
"action of wearing" (clothes), mid-15c., from wear (v.). Meaning "what one wears" is 1560s. To be the worse for wear is attested from 1782; noun phrase wear and tear is first recorded 1660s, implying the sense "process of being degraded by use."
Old English werian "to clothe, put on, cover up," from Proto-Germanic *wasīn- (source also of Old Norse verja, Old High German werian, Gothic gawasjan "to clothe"), from PIE *wos-eyo-, suffixed form of *wes- (2) "to clothe," extended form of root *eu- "to dress."
The Germanic forms "were homonyms of the vb. for 'prevent, ward off, protect' (Goth. warjan, O.E. werian, etc.), and this was prob. a factor in their early displacement in most of the Gmc. languages" [Buck]. It shifted from a weak verb (past tense and past participle wered) to a strong one (past tense wore, past participle worn) in 14c. on analogy of rhyming strong verbs such as bear and tear. Secondary sense of "use up, gradually damage" (late 13c.) is from effect of continued use on clothes. To wear down (transitive) "overcome by steady force" is from 1843. To wear off "diminish by attrition or use" is from 1690s.
early 15c., "prepared," from the verbal phrase make ready (mid-14c. as "prepare;" late 14c. as "put in order"); see make (v.) + ready (adj.). Applied figuratively, and often disparagingly, to a thing or person seeming to exist in a finished or complete form (1738). As the name of a dada art style, 1915 (Duchamp). Ready-to-wear, of clothing, "ready made," is by 1890.
"ready, prepared," Old English gearo "ready, prepared, equipped," from gearwian "to equip, prepare" (related to gearwe "clothing, dress") from Proto-Germanic *garwjan "to make, prepare, equip, ready, complete" (see gear (n.)). Cognate with German gar, Dutch gaar. Related: Yarely.
c. 1500, from adjectival use of past participle of wear (v.); from Old English geworen. Worn-out "exhausted by wear, made ineffective by overuse" is attested from 1610s in reference to things, c. 1700 in reference to persons.