IPA: /ˈfeɪt.fəl/
KK: /ˈfeɪtfəl/
Having a significant impact on future events, often in a negative or disastrous way.
The fateful decision to ignore the warning led to serious consequences.
Fateful → It is formed from "fate" (from Latin *fatum*, meaning that which has been spoken or decreed) and "-ful" (meaning full of). The word "fateful" means full of fate or having significant consequences determined by fate.
Think of 'fate' as something that has been 'decreed' and remember that 'fateful' means full of significant consequences.