Pronunciation: (ri-tärd', for 1–3, 5; rē'tärd for 4),[key] —v.t. to make slow; delay the development or progress of (an action, process, etc.); hinder or impede.
—v.i. to be delayed.
—n. 1. a slowing down, diminution, or hindrance, as in a machine.
a. a mentally retarded person.
b. a person who is stupid, obtuse, or ineffective in some way: a hopeless social retard. 3. Auto.,Mach.an adjustment made in the setting of the distributor of an internal-combustion engine so that the spark for ignition in each cylinder is generated later in the cycle. Cf. advance.