Retardant (noun)

1. A substance or agent that slows down or delays a process or reaction.
2. A substance that reduces the rate of combustion in a fire.

Origin:

From the verb retard, meaning "to slow down or delay something", and the suffix -ant ("a substance or agent that causes a particular effec.t")

Examples:

1. The fire retardant was sprayed on the building to slow down the spread of the fire.
2. The paint contains a flame retardant to make it safer.
3. The retardant was added to the fuel to reduce emissions.
4. The retardant was used to slow down the chemical reaction.
5. The retardant is used to slow down the drying time of the paint.