delusion

1. N-COUNT A delusion is a false idea. 错觉

I was under the delusion that he intended to marry me. 我有一种错觉，他要娶我。

2. N-UNCOUNT Delusion is the state of believing things that are not true. 妄想

Insinuations about her mental state, about her capacity for delusion, were being made. 当时有对她的精神状态的影射——说她有妄想症的影射。