This is the 13482nd most frequent Russian word.
напрочь
Completely; utterly; entirely.
The word 'напрочь' emphasizes totality, showing that the action of forgetting was complete and absolute.
Он напрочь забыл о встрече.
He completely forgot about the meeting.
In this sentence, 'напрочь' is used to indicate that the hopes were not just diminished but entirely eradicated.
Дождь уничтожил напрочь все надежды на пикник.
The rain completely destroyed all hopes for a picnic.
Here, 'напрочь' denotes a resolute and uncompromising refusal.