To writhe or struggle in severe pain or anguish; to suffer convulsively or agonizingly.
病人はベッドの上でもがき苦しんでいた。
The patient was writhing in agony on the bed.
借金問題に追い詰められ、夜も眠れずにもがき苦しんだ。
Pursued by debts, he couldn't sleep at night and writhed in anguish.
呼吸が苦しくなり、患者がもがき苦しむ様子が見られた。
He showed signs of struggling for breath and writhing in agony.