retardant
Americannoun
adjective
noun
adjective
Other Word Forms
- retardance noun
- retardancy noun
Etymology
Origin of retardant
Explanation
A retardant is anything that prevents something from happening, or inhibits it from growing or spreading. Using a rust retardant on your car, for example, should help keep it from getting rusty. A fire or flame retardant is a type of chemical that stops fire from starting or spreading. Sometimes fire retardants are sprayed or dumped on a fire to put it out, like the foam fire retardant you might spray from a hand-held fire extinguisher onto a grease fire in a kitchen. Retardant comes from the verb retard, "make slow, or make slower."
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.
If the cameras and heat sensors around the house detect danger, the system can envelop the home in over 1,000 gallons of fire retardant and hundreds of gallons of fire-suppressing foam.
From Los Angeles Times • Mar. 2, 2026
Among the synthetic products, 19 claimed to be flame retardant, three were labeled water resistant, nine advertised heat resistance, and three promoted "green" claims such as "no PVC" or "non-toxic."
From Science Daily • Feb. 19, 2026
Professor Edwin Galea, from the University of Greenwich, said the effectiveness of retardant treatment on PU foam can wear off over time.
From BBC • Jan. 2, 2026
Fire crews typically use tanker trucks to bring water, and also rely on helicopters and planes to drop water and retardant on fires.
From Los Angeles Times • Dec. 17, 2025
She worried that all the chemicals in the fire retardant couldn’t be good for him, but at least it had protected him a little.
From "Two Degrees" by Alan Gratz
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
