What does CRITICAL mean?

adjective

1. marked by a tendency to find and call attention to errors and flaws“a critical attitude”
2. at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction“a critical temperature of water is 100 degrees C--its boiling point at standard atmospheric pressure”
3. characterized by careful evaluation and judgment“a critical reading”
4. urgently needed; absolutely necessary“a critical element of the plan”
5. forming or having the nature of a turning point or crisis“a critical point in the campaign”
6. being in or verging on a state of crisis or emergency“a critical shortage of food”
7. of or involving or characteristic of critics or criticism“critical acclaim”