耆
キ, シ, おい.る

senility

JLPT0 G13 S0 F5000

An abbreviated form of 老 (aged) + 旨# tasty → the delicious *taste* of cured/preserved food. This primary sense largely faded, with 耆 coming to refer to instead to human *aging* and/or senility. Compare 嗜, which was devised to replace 耆.

[Full Kanji Etymology List]