禍根(かこん)

root of evil; source of trouble

禍福(かふく)

fortune and misfortune

惨禍(さんか)

catastrophe; disaster

舌禍(ぜっか)

trouble caused by one's words

禍々(まがまが)しい

ominous; sinister

災禍(さいか)

disaster; calamity

戦禍(せんか)

ravages of war

水禍(すいか)

flood disaster; water-related disaster

火禍(

戦禍(せんか)で多(おお)くの家(いえ)が焼(や)けた。

Many houses were burned in the ravages of war.

その事件(じけん)は社会(しゃかい)に深(ふか)い禍根(かこん)を残(のこ)した。

That incident left a deep-rooted grievance in society.