Southern colloquialism
def., ghost, apparition, lost soul

The safeguarding of Earth and other worlds from biological cross-contamination (i.e. billionaires with too much time on their hands).

Also known as “planetary protection.” Planetary protection / quarantine “reflects both the unknown nature of the space environment and the desire of the scientific community to preserve the pristine nature of celestial bodies until they can be studied in detail.”

There are two types of interplanetary contamination. Forward contamination is the transfer of viable organisms from Earth to another celestial body. Back contamination is the transfer of extraterrestrial organisms, if such exist, back to the Earth's biosphere.

A ghost; a haunt; a spirit.

Chiefly Southern U.S. var of haunt, originally, but the meaning has since morephed to mean more than a ghost. It can also mean a scary bitch or mean person, usually a woman.

In western North Carolina, a haint is a ghost, a spook, but not the booger man.

In West Virginia it's a ghost

noun,

1. A hateful bitch.

2. A truly heinous she-devil so brutal that anachronistic and unusual colloquial slang is called for.