A type of UFO occupant. Typically diminutive, grey-skinned being with large black eyes, frail body and a slit for a mouth. The also have flat, duck-like feet but this is never shown in films or TV as undermines their sinister, ethereal quality.

Purportedly from the Zeta Reticuli star system but fond of hanging around the mid-western United States, waiting to fondle truckers, rednecks, fishermen, loggers and people looking for a publisher.

Abilities; walking into locked rooms, designing and flying circular craft, turning radios on and off with science/telepathy, levitation and fingering orifices.

First appearance in fiction; possibly the work of HG Wells.
Witness 1; wait!... what are those beings in the clearing... my God!
Wotness 2: Oh they're just Greyliens. They aren't famous aliens like Klaatu and Gort.
Witness 1; or Han and Chewie.
Witness 2: is Han an Alien?
Witness 1; technically he was.

Greyliens return to saucer, feeling despondent. Nobody notices.
by Klaatu's Nikto October 12, 2020
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A person who is not full white and not full black. Commonly known as a greylien. Other variations include "grey mysterio" for a greylien that is mysterious.
Hide your sheep the greylien is coming over soon.
by miguel8o September 22, 2017
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An aborted concept in this realm where once beautiful beings go down any series of terrible evolutionary paths and result in a very small number of emotionless, blank-eyed beings that are only concerned with darting around the Universe really quickly to find what they once were or could've become.
Greyliens always crash land and die or fly back to wherever they came from when they discover homo sapiens on the third rock from this one sun in the milkyway. Same goes for the greenies. Horses hate Greyliens and so do Orcas, they like the ones with long hair and colored eyes.
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