IPA: /ˈkrɪtɪklnəs/
KK: /ˈkrɪtɪkəlnəs/
The state or quality of being very important or serious.
The criticalness of the situation required immediate action.
Criticalness → It is formed from "critical" (from Greek "kritikos", meaning able to judge) and the suffix "-ness" (meaning the state or quality of). The word "criticalness" refers to the state of being critical or the quality of being able to judge or evaluate.
Think of the ability to 'judge' ('kritikos') something and the 'state' ('-ness') of being able to do so — that's why criticalness means the quality of being critical.