This is the 9704th most frequent Japanese word.
苦悶
Agony; anguish; torment.
In this sentence, '苦悶' refers to the physical or emotional agony displayed through facial expressions.
彼は苦悶の表情を浮かべていた。
He had an expression of agony on his face.
Here, '苦悶' conveys the idea of ongoing emotional or physical distress experienced by a person.
彼女が苦悶しているときに手助けすることができたらと思う。
I wish I could help her when she is in agony.
In this instance, '苦悶' is employed to describe the intense, poignant struggle or emotional torment faced by the character within the story.