noun, noun or participle which takes 'suru', intransitive verb, noun which may take the genitive case particle 'no'
Describes deep mental or physical suffering, often with a literary or intense tone. Can be used as a noun, with する to mean 'to be in anguish', or as a no-adjective.
彼は失恋の苦悶に耐えられなかった。
He couldn't bear the anguish of a broken heart.
患者は痛みに苦悶している。
The patient is writhing in agony.
苦悶の表情を浮かべる。
To wear an expression of anguish.