Fatal-Fateful | Commonly Confused Words

Fatal

/ˈfeɪtl/

Causing death or leading to failure or disaster

who in his fatal freshness instantly replies: 'Thank you.How fatal that would be!But a delay might be fatal.

/ˈfeɪtfəl/

Causing an important or often unpleasant event

The fateful encounter changed her life forever.On that fateful day, everything went wrong.His fateful decision sealed their fates.

Fatal relates to death or being deadly, so think of it as connected to fate's ultimate end.
Fateful is about destiny or having significant consequences, not necessarily deadly.
To remember fatal, link it with fatality or a fatal accident, which suggests life-threatening.
Fateful often describes events with a big impact on the future, like a fateful decision.
Both words share the root fate, but fatal focuses on death, while fateful emphasizes significance.