That’s how well the car is protected from rust - a higher value means a lower risk of corrosion.
I know there is already another car with that name, which you can find here, but that one was not made in 4.2 (which CSR 144 is using). Anyway, this Accipiter reminds me of a first-gen LS400/Celsior from the front, with a rear end reminiscent of an S13 Silvia of the same vintage - and it all flows together beautifully.