retard

from The Century Dictionary.

• noun Retardation.
• To make slow or slower; obstruct in motion or progress; delay; impede; clog; hinder.
• To defer; postpone; put off.
• Synonyms To detain, delay.
• To be delayed or later than usual.

from the GNU version of the Collaborative International Dictionary of English.

• noun Retardation; delay.
• noun Colloq. and disparaging A mentally retarded person.
• noun Colloq. and disparaging a person who is stupid or inept, especially in social situations.
• noun the interval between the transit of the moon at which a tide originates and the appearance of the tide itself. It is found, in general, that any particular tide is not principally due to the moon's transit immediately proceeding, but to a transit which has occured some time before, and which is said to correspond to it. The retard of the tide is thus distinguished from the lunitidal interval. See under Retardation.
• intransitive verb obsolete To stay back.
• transitive verb To keep delaying; to continue to hinder; to prevent from progress; to render more slow in progress; to impede; to hinder; ; -- opposed to accelerate.
• transitive verb To put off; to postpone

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Retardation; delay.
• noun slang, offensive A person with mental retardation.
• noun slang, offensive A stupid person, or one who is slow to learn.
• verb transitive To keep delaying; to continue to hinder; to prevent from progress; to render more slow in progress; to impede; to hinder
• verb transitive To put off; to postpone.
• verb transitive, obsolete To be slow or dilatory to perform (something).
• verb intransitive To decelerate; to slow down.
• verb intransitive, obsolete To stay back.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb lose velocity; move more slowly
• noun a person of subnormal intelligence
• verb cause to move more slowly or operate at a slower rate
• verb be delayed
• verb slow the growth or development of