probsn't
Short for "probably not", just as "can't" is short for "can not".
Friend: "Yo, wanna smoke an j of dank with me and go see an awesome comedy?"
You: "Probsn't. I'd rather smoke a fat bong bowl with you and go to Mongolian BBQ."
You: "Probsn't. I'd rather smoke a fat bong bowl with you and go to Mongolian BBQ."