Something absolutely immense that has a lot of weight/mass. See also Carol Messer.

its the exit for your food; also known as the asshole; so tight it may do you like a real space blackhole, you may never get your tool back

A black person that is also an asshole.

When someone, usually after some type of romantic encounter, chooses to look two inches above your head to avoid eye contact as if you are a black hole.

When a penis gets stuck in a vagina during coital interactions, as if the penis got vacuumed by a Hoover Dirt Devil.

A single point of infinite density and mass. Blackholes mass is so great that nothing can escape it's gravitational pull, not even light.
Blackholes are supposedly a reality but there is no way (currently) to prove that they are what they are. Blackholes are created by a star or planet of great mass exploding and then collapsing in on itself creating a gravitational pull that just pulls everything in more eventually ending in a blackhole. Blackholes are often identified by circles of light that orbit them because of the gravity. Blackholes also give off X-Ray and infared signals making them easier to discover.
Blackholes are often theorized as tears in the time-space continuum meaning they can be portals to other points in space or time. Many sci-fi books and movies theorize blackhole possibilities, such as L. Ron Hubbard's "Mission Earth" novels using blackholes as an energy source.

The sick-to-gut feeling you get when your favorite radio station plays soundgarden's blackhole sun song way too much.

Dropping all forms of communication with someone you can't stand.Usually done without prior warning.
In networking, black holes refer to places in the network where incoming traffic is silently discarded (or "dropped"), without informing the source that the data did not reach its intended recipient so...

A girl who's vag is SO wide and SO deep you can't see the end of it. Nothing can escape it