Periodt (or period) is mostly used by The Gen-Z. It's basically "End of conversation," but it can be complient meaning "You tell 'em" or "You go girl," ect.
Meaning "period" as in what is put at the end of a sentence. The origin of this use of this word is in AAVE and Black Slang, and has been popularized widely on the internet. Used to express that your word is final and that you are in the right. Often said after making a statement.
The Wiggette version of "period" or "and that's final".
Used at the end of a sentence or argument when the speaker has a very high amount of (usually misplaced) confidence that they are in the right.
Also occasionally slapped onto the end of some really basic motivational quotes to put on Instagram or Snapchat to make it seem as if the poster is saying something incredibly revolutionary or meaningful when in fact they pulled the quote from a BuzzFeed list made back in 2016.
A word k-pop stans use to mean yes, or truthful. Most people that use this word will try and tell you to kill yourself if you don't like kpop, so beware.