This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 耹 is uncertain. It visually combines 耳 (ear) and 今, but the original semantic and phonetic roles are unclear.
The kanji has 耳 (ear) and 今 (now). Imagine listening carefully right now, but remember that the actual meaning is uncertain.
For キン, picture a king (キン) leaning in with his ear to hear a secret: king -> キン, and the ear 耳 is listening now 今.