Definition of: retard

(ri·tärd′) v.t.
To cause to move or proceed slowly; hinder the advance or course of; impede; delay.
—v.i. To be delayed. See synonyms under HINDER, OBSTRUCT.
—noun Delay; retardation. [<F retarder <L retardare <re- back + tardare make slow <tardus slow]
—re·tard′a·tive adjective
—re·tard′er noun