Is it "Fast"? Is it "Furious"? Both "Fast AND Furious"? Is it an increasingly rare case of being excessively fast and furious (i.e., "2 FAST, 2 FURIOUS")? Such is the question with every Fast/Furious sequel, as the series' naming convention is based wholly on whatever comes to Vin Diesel in a dream.
But as for the eighth film in the franchise, we can now stop wondering, as Diesel has revealed the sequel's official title:
Let your tattoo artist know: they can finally finish your back piece.