When someone named Jony/Jonas/Johnny acts crazy, or when one does stupid shit together with this person.
Matej: Yo, is that Jony over there? Why is he acting so goofy?
Krystof: Yeah, don't worry bro, he's just jonnin...
Krystof: Yeah, don't worry bro, he's just jonnin...
by crushingsculptures April 14, 2021
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