To get moded, told so bad that there's nothing you can say in your defense, be put in your place, or be embarassed like when you trip and someone sees you.
"Why'd I for real trip down the stairs the other day? I was SO clownt"
To disprove and/or embarrass by means of scientific proof or otherwise. Sometimes, but not always accompanied by "Witness!", or at least one or more people witnessing the clown.
"Naw Antoine, you was wit dat hoe all night!" "Aww clownt!" "That's a clown!" "Witness!"