Fatal

From Middle French fatal, from Latin fÄtÄlis ("fatal").

Full definition of fatal

1935, George Goodchild, Death on the Centre Court Chapter 1, She mixed furniture with the same fatal profligacy as she mixed drinks, and this outrageous contact between things which were intended by Nature to be kept poles apart gave her an inexpressible thrill.

1893, Walter Besant, The Ivory Gate Chapter Prologue, Such a scandal as the prosecution of a brother for forgeryâ€”with a verdict of guiltyâ€”is a most truly horrible, deplorable, fatal thing. It takes the respectability out of a family perhaps at a critical moment, when the family is just assuming the robes of respectability:...it is a black spot which all the soaps ever advertised could never wash off.

Causing death or destruction.
a fatal wound; a fatal disease; a fatal day; a fatal error

2013, Philip J. Bushnell, Solvents, Ethanol, Car Crashes & Tolerance, Surprisingly, this analysis revealed that acute exposure to solvent vapors at concentrations below those associated with long-term effects appears to increase the risk of a fatal automobile accident. Furthermore, this increase in risk is comparable to the risk of death from leukemia after long-term exposure to benzene, another solvent, which has the well-known property of causing this type of cancer.

(computing) Causing a sudden end to the running of a program.
a fatal error; a fatal exception

(plural fatals)

1999, Flying Magazine (volume 126, number 4, April 1999, page 15)The best accident rate in general aviation is in corporate/executive flying at 0.17 per 100000 hours for fatals and .50 for total accidents.