fa ‧ tal ‧ ly /ˈfeɪt ə l-i/ BrE AmE adverb
1 . in a way that causes death
fatally injured/wounded
Two officers were fatally injured in the explosion.
2 . in a way that will make something fail or be unable to continue
fatally flawed/weakened/damaged etc
Bolton’s idea was fatally flawed.
He has been fatally undermined by his own finance minister.