retardant

Etymology

Borrowed from French retardant, equivalent to retard (“to slow down”) + -ant.

adj

  1. Serving to impede (slow down) the action of something

noun

  1. Something that serves to retard (slow down) the action of something.“It took until last year for mattresses and furniture containing the highly toxic retardant deca-BDE to be banned, under European law, from sale. […] To make matters worse, far from saving us from fires, flame retardants appear to increase the risk.”