re·tar·dant 
/rɪˈtɑɚdn̩t/ adjective
always used before a noun /rɪˈtɑɚdn̩t/ adjective technical : able to slow down the progress or development of something — usually used in combination ▪ flame-retardant fabrics [=fabrics that do not catch fire easily]
— retardant noun, plural retardants [count]
▪ a fire retardant
▪ a fire retardant
