When a person makes a mistake and it's stupid. A STUpid mistake applies to people with the name Stu or Stuart.
Stu: "I tried to cut a guy off in traffic, but he wouldn't let me, so I started tailgating him, but then he slammed on his breaks, ran up to my car and scared the sh*t out of me."
Michael: "Well that was a STUpid mistake."
Michael: "Well that was a STUpid mistake."
by TPCJ September 2, 2009