You can use the word mess after someone says or does something that's embarrassing, stupid, pathetic, ridiculous, or weird. Honestly can be used after a lot of things. Even sometimes when you don't know what to reply, "mess" might work.
It's so hard to define mess... Mess. Check examples for a better understanding.
Sometimes has a t at the end. (Messt)

A person or people that purposefully causes chaos or mischief within a group for the sake of entertainment.

When someone is really funny

A person whose life has fallen into disrepair. Or one who is suffering the effects of intoxicating substances, perhaps on a prolonged basis.

An overly clumsy person who seems to have no control over his/her body.

to engage in an act of self pleasure

1. to hang out with a person with the intention of getting together and/or date. Term used in the south.

2. to be involved in the period before dating a person.