Webster's Revised Unabridged Dictionary · 1913

Rash

Rash (rash) , transitive verb

[For arace.]

1.
To pull off or pluck violently. [Obsolete]
2.
To slash; to hack; to cut; to slice. [Obsolete]
Rashing off helms and riving plates asunder. — Spenser

Rash , noun

[Old French rasche an eruption, scurf, French rache; from (assumed) Late Latin rasicare to scratch, from Latin radere, rasum, to scrape, scratch, shave. See Rase, and compare Rascal.]

(Medicine) A fine eruption or efflorescence on the body, with little or no elevation.
Collocations (4)
Canker rash , See in the Vocabulary.
Nettle rash , See Urticaria.
Rose rash , See Roseola.
Tooth rash , See Red-gum.

Rash , noun

[Compare French ras short-nap cloth, Italian & Sp. raso satin (compare Rase); or compare Italian rascia serge, German rasch, probably from Arras in France (compare Arras).]

An inferior kind of silk, or mixture of silk and worsted. [Obsolete] — Donne

Rash (-ẽr) , adjective

[Probably of Scand. origin; compare Danish & Swedish rask quick, brisk, rash, Icelandic roskr vigorous, brave, akin to Dutch & German rasch quick, of uncertain origin.]

1.
Sudden in action; quick; hasty. [Obsolete]
Strong as aconitum or rash gunpowder. — Shakespeare
2.
Requiring sudden action; pressing; urgent. [Obsolete]
I scarce have leisure to salute you, My matter is so rash. — Shakespeare
3.
Esp., overhasty in counsel or action; precipitate; resolving or entering on a project or measure without due deliberation and caution; opposed to prudent; said of persons; as, a rash statesman or commander.
4.
Uttered or undertaken with too much haste or too little reflection; as, rash words; rash measures.
5.
So dry as to fall out of the ear with handling, as corn. [Provincial English] — Grose
Was never known a more adventurous knight. — Dryden
Her rash hand in evil hour Forth reaching to the fruit, she plucked, she eat. — Milton
If any yet be so foolhardy To expose themselves to vain jeopardy; If they come wounded off, and lame, No honor's got by such a maim. — Hudibras

Rash (rash) , transitive verb

To prepare with haste. [Obsolete] — Foxe