The term no non-sense means to be completely free of any non-sense when preparing to do something. Commonly used in video games, when you're about to give kids some scrape. When one is no non-sense, they should not be taken lightly, because to them, you are non-sense, which is what they are totally opposing. No non-sense can be used as a verb or adjective.
"Yo, I'm f*cking no non-sense today, don't f*ck with me*" (Adj.)
"Yo, you went no-nonsense just now! I was mad scared!" (Verb)