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obsession; compulsive idea
火の消し忘れの強迫観念が彼を苦しめる。
The obsessive idea of leaving the stove on torments him.
彼は強迫観念から解放された。
He was freed from his compulsive thoughts.
彼女は誰かに見られているという強迫観念に囚われていた。
She was trapped by the obsessive idea that someone was watching her.