retard

To retard something is to hold it back, or slow it down.

Example: He cut back the shrub to retard its growth.

A retard in music is an instruction to slow down the tempo.

See retardation. The state of being delayed.

A retard is someone who is mentally disabled or a very slow learner.

Example: I've been showing my co-worker for a whole year how to properly seal the bags together and he still doesn't do it right, god what a retard.