Retard was a derogatory term for someone who was mentally handicapped or their social and/or intellectual capacity was well below average.
An agent from the FBI became frustrated with Commander Pavel Chekov while interrogating him. Chekov's "playing dumb" routine caused the agent to question his mental status. (Star Trek IV: The Voyage Home)
- "What do you think?"
- "He's a Russkie."
- "That's the stupidest thing I've ever heard in my life. Of course he's a Russkie but he's some kind of retard or something."
- "We better call Washington."
- - Agent #1 and Agent #2