To flaunt is to display something ostentatiously — flaunt your wealth. To flout is to openly disregard a rule or convention — flout the regulations. "Flaunting the law" is the common error; rules are flouted, not flaunted.
The core difference
Showing off, and open defiance.
- flaunt — display ostentatiously: flaunting her success.
- flout — openly disregard: flouting the ban, flout convention.
The error and why it persists
"Flaunting the rules" appears constantly, and there is a logic to it — openly breaking a rule does involve a kind of display. But the words are distinct, and the confusion has been widespread enough for long enough that some dictionaries note it while still marking it as disputed.
The phrase
If you've got it, flaunt it uses the display sense correctly. That is the sentence to anchor the word to, because it is unambiguous.