when one squeezes their ass cheeks together.
person 1: why does your ass look so toned?
person 2: im clenching my cheeks together.
by olaf the pimp December 12, 2006
when your pussy quakes and tightens at the thought or sight of something nut worthy.
when i saw that video of jacob sartorious, i clenched immediately
by mcmilner January 4, 2018
adj. - When you have little time to do something; close; difficult.

Not to be confused with what you do to with your ass cheeks to prevent poop from involuntarily exiting.
"We have to be there in 5 minutes, it's gonna be pretty clench."

"I have all day surfing lessons for the next few weeks; my schedule is pretty clench right now."

"The exam had so much on it I barely finished. It was pretty clench."
by poopmasterappleseedbingboi April 10, 2011
<person1 and person2 punch fists together>
Person1+2: "Clench!"
by Pete J October 11, 2003
Jaw clenching caused as a side-effect of consuming LSD. Generally not dangerous. Treated by staying hydrated and exercising the mouth. Nothing to worry about as worrying can cause a bad trip.
Luke: You just gotta watch out for The Clench
A.J. (On LSD): The Clench? Wtf is that?
Luke: You don't know about The Clench man? That shit will lock your mouth shut!
by deadheadkid92 August 10, 2010
When a woman's uterus and vagina contract causing unbelievable pleasure course through her body.
My lower belly clenched in anticipation of his cock. I could imagine it like it was happening. As my vagina was clenching, all over my body pleasure ran through my veins.
by Kittenliar January 16, 2018
To hold a shit in for a long time, especially when it's not an appropriate time to take a dump.
I've been clenching ever since I got to work.
by superhog May 18, 2006