환청이 · 환청을
auditory hallucination, hearing voices
Example
밤새 잠을 못 자서 환청이 들리는 것 같아요.
I haven't slept all night, so I think I'm hearing things.
Word parts
환 illusion+청 hear
Literally 'illusory hearing'.
Good to know
Used with 들리다: 환청이 들리다 (to hear voices); jokingly said when you think you misheard.