ASIL
Beginner
A safety grade from A to D for how dangerous a failure would be. D is the strictest.
Novice
Automotive Safety Integrity Level. Each hazard is rated for how severe the harm would be, how often the driving situation occurs, and how well a driver could still control the car; a table combines the three into QM (ordinary quality, no safety requirement) or ASIL A to D, with D the strictest.
Expert
Sets the hardware metric targets (SPFM, LFM, PMHF), the required methods and how independent the confirmation reviews must be. ASIL decomposition can split one requirement across redundant, independent elements at lower ASILs.
Explained in Automotive (Industries).
See also: Single-point fault metric (SPFM), Latent fault metric (LFM).