When someone is acting sus, shifty, or shady, but to an extreme degree.

Commonly used with the thinking face emoji to denote skepticism.
Bob: Hey, do you know what's going on over at that street corner? 🤔🤔🤔
Joe: No, but it's sus level 100 for sure
by Talkohh August 1, 2017
Get the sus level 100 mug.