This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 聭 is uncertain. It combines 耳 (ear) and 鬼 (demon/ghost), but the original semantic or phonetic motivation is unclear.
With 耳 (ear) and 鬼 (demon), imagine a demon whispering shameful things into your ear, making you feel embarrassed. This fits the kun readings related to shame.
For キ, imagine a key-shaped ear demon that unlocks your embarrassment: key -> キ, and the ear demon makes you feel ashamed.