Klingons are a fictional alien species in the Star Trek universe. They are typically characterized as a warrior race and are known for their aggressive behavior and militaristic culture. The term Klingons, e.g. is used to refer to any similar alien species. The crossword solutions for this term are ALIENS (6 letters) and ETS (3 letters). ALIENS is a term used to refer to any extraterrestrial life form, while ETS is an acronym for Extra-Terrestrial Species.