Definitions

1. noun

a device or substance that slows down the rate of something, such as a chemical reaction or the wear on a mechanical part

“The engine’s retarder helped it climb the steep hill with ease.”

2. noun

a person or thing that causes a delay or hindrance

“The bad weather was a retarder to our plans to go on a hike.”

3. verb

to slow down or delay the rate of something

“The engineer tried to retard the chemical reaction to prevent an explosion.”