What is the meaning of critical?

adjective

• Marked by a tendency to find and call attention to errors and flaws.
  • usage: "a critical attitude"
• At or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass to sustain a chain reaction.
  • usage: "a critical temperature of water is 100 degrees C-its boiling point at standard atmospheric pressure"; "critical mass"; "go critical"
• Characterized by careful evaluation and judgment.
  • usage: "a critical reading"; "a critical dissertation"; "a critical analysis of Melville's writings"
• Urgently needed; absolutely necessary.
  • usage: "a critical element of the plan"; "critical medical supplies"; "vital for a healthy society"; "of vital interest"
  • synonyms: vital
• Forming or having the nature of a turning point or crisis.
  • usage: "a critical point in the campaign"; "the critical test"
  • synonyms: decisive
• Being in or verging on a state of crisis or emergency.
  • usage: "a critical shortage of food"; "a critical illness"; "an illness at the critical stage"
• Of or involving or characteristic of critics or criticism.
  • usage: "critical acclaim"