1. (

• dangerous ,
• grave ,
• grievous ,
• serious ,
• severe ,
• life-threatening

) causing fear or anxiety by threatening great harm; "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" ;

2. (

• grievous ,
• heartbreaking ,
• heartrending

) causing or marked by grief or anguish; "a grievous loss"; "a grievous cry"; "her sigh was heartbreaking"; "the heartrending words of Rabin's granddaughter" ;

3. (

• grave ,
• grievous ,
• heavy ,
• weighty

) of great gravity or crucial import; requiring serious thought; "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" ;

4. (

• atrocious ,
• flagitious ,
• grievous ,
• monstrous

) shockingly brutal or cruel; "murder is an atrocious crime"; "a grievous offense against morality"; "a grievous crime"; "no excess was too monstrous for them to commit" ;