Slack-jawed idiot 

Anyone posing for a clickbait Youtube thumbnail.

No that's not a good pose you slack-jawed idiot.

Slack-jawed idiot by BlitzofChaos July 12, 2021

slack jawed yokel

Person (usually refering to a male though not gender bias) maintaining little to no decernable speaking skills often associated with one who fornicates with barn yard animels.

Dag yo, the slack jawed yokel jus done it to a pig.
also portrayed in a Simpsons episode to the song "some folk el never lose a toe and then again some fok'll, Cletis the slack jawed yokel"

slack jawed yokel by webtech May 10, 2005

slack-jawed faggot 

refering to one who has lost control of the joint efforts of both mouth and jaw muscles, due to arthritis commonly associated with a long history of performing fellatio

Wow, Bruce is such a slack-jawed faggot, that he could barely keep his lover's load refrained to his mouth and chin.

slack-jawed faggot by alex December 29, 2004

Slack Twat 

When a woman becomes lazy and doesn't shave, wash or take proper care of her vagina

I pulled down her pants and bammm, she had a slack twat

Slack Twat by Matt Harding April 14, 2008

Slack-Arena 

An area of your office that pretends to be "busy-busy" working, when in actuality only catching up on Facebook and Myspace, making their weekly sporting picks, analyzing their fantasy football teams, and shopping online for Manpons (see manpon.) The productive area of the office, known as the "Engine Room" completes the majority of the work - however - the Slack-Arena is quick to take credit for this work.

A slack-arena is made up of multiple slackerinos - see slackerino
"The Slack-Arena at my office is 50% of the employees but probably only actually completes 25% of the work!"

Slack-Arena by NIETS January 26, 2009

slack palmful 

A large handful of something

Hey, Gretchen, you couldn't fetch me a slack palmful of eyelets?

slack palmful by Zeta +Shaun January 17, 2008

Slack-Jack 

A complete and utterly terrible handjob. One that is simply not worth the time and honestly makes one wonder what the fuck is wrong with with the human being who's head is in your lap.

Brady came back Jones' house and told everyone that Liz gave him the Slack-Jack of the century and he'd rather stick his dick in a pinecone than experience that again.

Slack-Jack by SpamoniJones April 6, 2010