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Synonyms

rash

1 American  
[rash] / ræʃ /

adjective

rasher, rashest
  1. acting or tending to act too hastily or without due consideration.

    Synonyms:
    foolhardy, indiscreet, precipitate, incautious, venturous, reckless, impetuous, hasty
    Antonyms:
    cautious
  2. characterized by or showing too great haste or lack of consideration.

    rash promises.


rash 2 American  
[rash] / ræʃ /

noun

  • rashes
    plural
  1. an eruption or efflorescence on the skin.

  2. a multitude of instances of something occurring more or less during the same period of time.

    a rash of robberies last month.


rash 1 British  
/ ræʃ /

adjective

  1. acting without due consideration or thought; impetuous

  2. characterized by or resulting from excessive haste or impetuosity

    a rash word

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

rash 2 British  
/ ræʃ /

noun

  1. pathol any skin eruption

  2. a series of unpleasant and unexpected occurrences

    a rash of forest fires

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What does rash mean? Rash describes acting too quickly and without proper planning, as in James was rash when he decided to quit his job after just one hard day. Rash also describes a great haste or a lack of consideration, such as Sahad avoided making rash decisions by doing a lot of research first. A rash is a skin condition, such as bumps or a red area, like you might get if you touch poison ivy. A rash is also several instances of something that occur at the same or nearly the same time, such as a rash of snowstorms over a week or a rash of electronic sales during the winter holidays. Example: He always jumps head first into rash decisions, but sometimes it works out.

Other Word Forms

Derived Forms

Inflected Forms

Nouns

Etymology

Origin of rash1

First recorded in 1350–1400; Middle English; cognate with Dutch, German rasch “quick, brisk,” Old Norse rǫskr “brave”

Origin of rash2

1700–10; < French rache (obsolete), Old French rasche skin eruption, derivative of raschier to scratch, ultimately < Latin rādere to scratch

Explanation

A rash is something that spreads like wild fire — red itchy skin or a series of unfortunate events. It can also describe an impulsive, wild decision. As an adjective, rash has meant "quick, vigorous" since the 1300s by way of Scotland. The meaning shifted to "reckless" a few hundred years later, and can still be used that way — a "rash decision" is a sudden, not well thought out one. Rash, the noun that no one wants on their skin, came a few hundred years after that, but from the French word rache which at some point meant "ringworm." Ringworm still gives us a red, itchy rash. Fun! Rash can also mean a lot of unpleasant things happening in a short amount of time, like robberies or earthquakes.

Keep Reading on Vocabulary.com

Vocabulary lists containing rash

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

An infected person can spread the disease up to four days before a measles rash appears and up to four days after the rash appears, according to the county department.

From Los Angeles Times Aug. 6, 2026

Elizabeth Hagerty told prison doctors she had heat rash covering her body and couldn’t keep fluids down; they sent her back to her cell, and she died two days later, a month short of release.

From Slate Jul. 31, 2026

Nothing rash, and nobody here is your financial adviser.

From MarketWatch Jul. 28, 2026

Her parents later noticed a rash beginning to form on her belly.

From BBC Jul. 8, 2026

“Don’t go doin’ nothing rash now, you hear?”

From "Water for Elephants" by Sara Gruen

People showed strange boils and rashes that volunteers photographed.

From Los Angeles Times Aug. 8, 2026

Measles causes fever, respiratory symptoms and skin rashes.

From Barron's Jul. 24, 2026

For those who do, the most common symptoms include high fever, headache, muscle and joint pains, nausea and rashes.

From BBC Jul. 23, 2026

Many couples say their marriage hinges on one party coming around to their spouse’s feline friends, which can mean dealing with severe rashes, smelly litter boxes and early wakeups.

From The Wall Street Journal Jul. 6, 2026

Then I get rashes and blisters, but my mother has creams that help.

From "A Thousand Splendid Suns" by Khaled Hosseini

As written, the recipe needs nothing more than a generous swipe of cultured butter and a plate of soft scrambled eggs, maybe a rasher of bacon if you’re feeling traditional.

From Salon Nov. 4, 2025

Braised wagyu beef cheek was less tender than it should have been, but butter and dark chocolate enriched the sauce, cambozola sharpened the accompanying gratin, and a crisp rasher of speck capped the dish.

From Seattle Times May 24, 2018

It didn’t have the toothsome texture or smoky depth of a rasher of butcher’s dry-cured bacon, but I’d happily buy it again as an alternative to “nitro-meat”.

From The Guardian Mar. 1, 2018

Matt made a sandwich with two angus patties with red onion, cheddar, caramelized onions, rasher bacon, grilled pineapple, a fried egg, tomato chili jam and aioli wrapped in lettuce.

From Time Aug. 4, 2015

“You give him some water and a rasher of bacon,” said Bono, “he’d go on for some time in this vein.”

From "The Astonishing Life of Octavian Nothing, Traitor to the Nation, Volume II: The Kingdom on the Waves" by M.T. Anderson

Show business is fear-driven, and that fuels Deborah and Ava’s rashest decisions more than anything else.

From Salon Apr. 10, 2025

But there were officials in place who could temper his rashest impulses.

From Washington Post Aug. 22, 2019

It wasn’t remotely the same, of course, and the overstatement rebounded against Strauss, who had never said anything of the kind but was soon being held accountable for the rashest words of his admirers.

From The New Yorker Oct. 17, 2016

He was the prettiest, the brashest, the baddest, the fastest, the loudest, the rashest.

From The Wall Street Journal Jun. 5, 2016

I suspect I am one of the rashest of existing men.

From The Moonstone by Wilkie Collins

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