incubus
/ˈɪŋkjʊbəs/noun
(pl. incubi /-baɪ/)
1- a male demon believed to have sexual intercourse with sleeping women梦淫妖（传说与熟睡女性发生性交）。
1.1
- figurative a cause of distress or anxiety〈喻〉极度苦恼的原因; 焦虑的原因：
debt is a big incubus in developing countries.
债务是发展中国家巨大的精神压力。
1.2
- archaic a nightmare〈古〉梦魇, 噩梦。
词源
Middle English: late Latin form of Latin incubo 'nightmare'， from incubare 'lie on' （see INCUBATE）.