奇异 (qíyì) can function as a noun meaning "strangeness" or "peculiarity." In this usage it refers to the quality of being unusual or extraordinary. It appears in literary or narrative contexts to describe an atmosphere or sensation that feels otherworldly.
这个地方充满了一种说不出的奇异。
Zhège dìfāng chōngmǎn le yī zhǒng shuō bù chū de qíyì.
This place was filled with an indescribable strangeness.
故事里弥漫着令人不安的奇异。
Gùshì lǐ mímàn zhe lìng rén bù'ān de qíyì.
The story was permeated with an unsettling strangeness.
她感受到了梦境中那种无法解释的奇异。
Tā gǎnshòu dào le mèngjìng zhōng nà zhǒng wúfǎ jiěshì de qíyì.
She felt that inexplicable strangeness in the dream.