Earther

Earther or Earthling was a derogatory term that was used in reference to humans in the 23rd century.

The term was most commonly used by the Klingons in the 2260s as tensions between the Federation and the Klingon Empire were at their highest. (TOS novel: Errand of Vengeance: The Edge of the Sword & episode: "The Trouble with Tribbles").