1) Maximum Collision Assurance System 2) Low quality synthetic longitudinal stability system that guarantees you will lawn dart without immediate recognition and subsequent action of pitch trim runaway.
If you don't recognize a pitch trim runaway in any airplane you shall MCAS.
Manoeuvring characteristics augmentation system, or more appropriately, money comes above safety, due to Boeing rushing the 737 max into market while it was unsafe for commercial use all because of money.
MCAS means money comes above safety due to Boeing hiding it and poorly coding it to read from a single angle of attack (AoA) sensor to rush the 737 max into market, hence putting money above safety.
The jolt of fear you get when your car's lane-assist feature fights with you for steering wheel control. (Named for the Boeing 737 Max's infamous maneuvering control augmentation system that took away control from the pilot.)
Person #1: "Wow, the steering wheel seems to have a mind of it's own!"
Person #2: "...MCAS Syndrome."