Stupid
Stupid or r****d were derogatory terms for someone whose intellectual capacity was (perceived as being) below average or handicapped.
In 1986, an FBI agent became frustrated with Commander Pavel Chekov's incoherent answers while interrogating him. Chekov's "playing dumb" routine caused the agent to question his mental status, referring to the Russian as a r****d. (Star Trek IV: The Voyage Home)
When Christine Chapel was a child, a girl called her stupid, which resulted in Chapel's protective pet Malamute Milo biting the girl. Chapel told the story to Spock in 2259. (SNW: "Spock Amok")