介
カイ, すけ, ゆき

jammed in, shellfish, mediate, concern oneself with

JLPT2 G7 S4 F617

?a variant form of 人 person + an element# indicating two sides → person intervening to reduce/eliminate distance between separate parties → *intervene*; *mediate*. *Shellfish* is a borrowed meaning.

[Full Kanji Etymology List]