What is the meaning of grievous?

adjective

• Causing fear or anxiety by threatening great harm.
  • usage: "a dangerous operation"; "a grave situation"; "a grave illness"; "grievous bodily harm"; "a serious wound"; "a serious turn of events"; "a severe case of pneumonia"; "a life-threatening disease"
  • synonyms: dangerous, grave, serious, severe, life-threatening
• Causing or marked by grief or anguish.
  • usage: "a grievous loss"; "a grievous cry"; "her sigh was heartbreaking"; "the heartrending words of Rabin's granddaughter"
  • synonyms: heartbreaking, heartrending
• Of great gravity or crucial import; requiring serious thought.
  • usage: "grave responsibilities"; "faced a grave decision in a time of crisis"; "a grievous fault"; "heavy matters of state"; "the weighty matters to be discussed at the peace conference"
  • synonyms: grave, heavy, weighty
• Shockingly brutal or cruel.
  • usage: "murder is an atrocious crime"; "a grievous offense against morality"; "a grievous crime"; "no excess was too monstrous for them to commit"
  • synonyms: atrocious, flagitious, monstrous