A fake mustache - often ridiculous looking and intended to be funny or ironic. It is most often seen on hipsters and is the primary basis of a mustache party.

It is believed that an individual is given special "douche powers" when wearing a musdouche, which make them intolerable to anyone other than legitimate douchebags and fellow musdouche wearers. Once the musdouche is removed, the individual in question typically returns to their normal state.

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.

noun, MUS-doosh, a douchey mustache. Usage is subjective but generally refers to a thin, closely cropped mustache.