rash

1 of 3

noun

ˈrash 

1

: an eruption on the body

2

: a large number of instances in a short period

a rash of complaints

rash

2 of 3

adjective

1

: marked by or proceeding from undue haste or lack of deliberation or caution

a rash promise

2

obsolete : quickly effective

rashly adverb

rashness noun

rash

3 of 3

adverb

archaic

: in a rash manner

Did you know?

Is it possible that the origins of the noun rash (referring to a group of red spots on the skin that is caused by an illness or a reaction to something) and the adjective rash (meaning “overly hasty”) are the same? Not so fast! Like many homonyms—“two or more words spelled and pronounced alike but different in meaning”—the two rashes have distinct sources. The noun rash, which first appeared in English in the late 17th century, probably comes ultimately from the Latin verb rādere, meaning “to scrape, scratch, shave.” The adjective rash appears to be about two centuries older, and comes from a Middle English word rasch meaning “active, quick, eager.”

Synonyms of rash

Adjective

• impulsive
• hurried
• sudden
• hasty
• rushed
• reckless
• precipitate
• precipitous
• overhasty
• cursory
• drive-by
• rapid
• headlong

Choose the Right Synonym for rash

adventurous, venturesome, daring, daredevil, rash, reckless, foolhardy mean exposing oneself to danger more than required by good sense.

adventurous implies a willingness to accept risks but not necessarily imprudence.

adventurous pioneers

venturesome implies a jaunty eagerness for perilous undertakings.

venturesome stunt pilots

daring implies fearlessness in courting danger.

daring mountain climbers

daredevil stresses ostentation in daring.

daredevil motorcyclists

rash suggests imprudence and lack of forethought.

a rash decision

reckless implies heedlessness of probable consequences.

a reckless driver

foolhardy suggests a recklessness that is inconsistent with good sense.

the foolhardy sailor ventured into the storm

Examples of rash in a Sentence

Noun

The baby has a skin rash.

The doctor said she developed the rash because of the medicine.

I break out in a rash if I eat shellfish.

Symptoms of the disease include rash and fever.

There has been a rash of robberies in the city this summer.

Adjective

Their rash actions resulted in a serious accident that could have killed someone.

Don't be rash about this decision. Take your time.

It was rash of you to make that promise.

Recent Examples on the Web

Noun

As a girl growing up in the 1970s, Griffin recalls how her parents and other neighbors in the two-street patch of homes did not let their children play at the nearby Fannie Robinson Park after some of them started developing rashes or getting sick. — Alisha Ebrahimji, CNN Money, 26 Sep. 2026

Short-term exposure to mold can cause sinus congestion, coughing, wheezing, eye irritation and skin rashes. — Rebecca Smullin Dawson, The Conversation, 25 Sep. 2026

Adjective

The viral disease causes a blotchy rash and flulike symptoms but can develop into severe, life-threatening illnesses, such as pneumonia and brain swelling. — Lauren J. Young, Scientific American, 18 Sep. 2026

Despite the defense allowing nine third down conversions to the Giants and allowing New York to win the time of possession battle by over 13 minutes, the Cowboys are not making any rash decisions after just one game. — Nick Harris, Fort Worth Star-Telegram, 18 Sep. 2026

Adverb

Measles rash appears three to five days after the first symptoms. — Janet Loehrke, USA Today, 18 Mar. 2026

Whatever is causing the left-hander to pitch terribly away from home this season, the Giants need to address this road rash sooner rather than later. — Andrew Baggarly, The Mercury News, 2 May 2017

Word History

Etymology

Noun

probably borrowed from 17th-century French rache, rasche, going back to Middle French raiche "tinea," noun derivative of racher "to chisel, groove (metal)" (probably also "to scrape, scratch," senses attested in Romance cognates), going back to Vulgar Latin *rāsicāre, verb derivative from Latin rās-, participial and nominal stem of rādere "to scrape, scratch, shave" — more at rase

Adverb

Middle English (northern dialect) rasch quickly; akin to Old High German rasc fast

First Known Use

Noun

1696, in the meaning defined at sense 1

Adjective

15th century, in the meaning defined at sense 1

Adverb

15th century, in the meaning defined above

Phrases Containing rash

• diaper rash
• heat rash
• nettle rash
• road rash

Rhymes for rash

• ash
• bash
• brash
• cache
• cash
• clash
• crash
• dash
• flash
• gash
• hash
• lash

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Kids Definition

rash

1 of 2 adjective

ˈrash 

: marked by or coming from being too hasty in speech or action or in making decisions

a rash promise

rashly adverb

rashness noun

rash

2 of 2 noun

1

: a breaking out of the skin with red spots

2

: many instances in a short time

a rash of fires

Medical Definition

rash

noun

ˈrash 

: an eruption on the body typically with little or no elevation above the surface