decisive + -ness

source: [RAIL WARS!の桜井あおいが導線を切断するGIF画像｜無料GIF画像検索 GIFMAGAZINE 657830]

1. the ability to make decisions quickly and effectively:

決断力、思い切りの良さ(↔ indecisiveness)

e.g. the crisis will require leadership and decisiveness to resolve it

e.g. he criticized the government for its lack of decisiveness.

2. the conclusive nature of an issue that has been settled or a result that has been produced:

断固［確固］たること、決意の現れ

e.g. there was no doubting the decisiveness of his victory

e.g. the decisiveness of the policy.