When someone does something that's uncalled for. Doing something out of context. Usually people act this way out of pettiness or drunk
"Nah bro, I love her and all but she was acting stupid. Had to take a break from her"

"I'd ask Katie to come drink, but she's a light weight and acts stupid when drunk"
by noturbae94 April 8, 2016
A sarcastic way of telling someone that what they just did was stupid and you hope they were only acting that dumb
Matt decided to sheet the wall before squaring it up. I told him to quit acting stupid
by Kook November 21, 2014
I often act stupider than I am, just to lead people off. I love to troll people and get their reactions
acting stupider than I am
by NASCAR MADAGASCAR January 12, 2021
An event or occurrence in which one person does or says something so brainless, so idiotic, so absolutely fucked-in-the-head that you begin to wonder whether you should point and laugh, or run away with overwhelming shame and embarrassment for the entire human race.

This always happens by one individual, without any outside influence. 100% natural stupidity.
"there were THIRTEEN cars off the road. THIRTEEN! i saw two separate three-car accidents, two 2-car accidents, and the rest were just individual acts of 'stupid'."

The worst offenders:
George W. Bush
Anna Nicole Smith
Amy Winehouse
Lindsay Lohan
Flava Flav
Paris Hilton
by a mother fucking genius January 3, 2013
the attempt of using nonexistent acting skills to look dumb - another way of getting yourself grounded, fucked up and/or in the hospital.
“She keeps acting stupid.”
by vanexla October 25, 2020