This is a clitic used by the streamer and Youtuber Wackawackamunv2, and it is used similar to a adverb, in the sense that it exaggerates something, but for this it does it to a whole other degree.
Person 1: Why do always go to Starbucks, a COFFEE shop, just to buy the least coffee'nis'tisity'ism thing on the menu?
Person 2: Why don't you mindd your own business?
Person 1: Fair.
Person 2: Why don't you mindd your own business?
Person 1: Fair.
by Dumb_Shit_Guy October 25, 2023