塞
ソク, サイ, ふさ.ぐ, とりで, み.ちる

close, shut, cover, block, obstruct

JLPT0 G7 S13 F5000

土# pile of earth + the upper element of 寒 (pile construction elements in raising a shelter) → plug/fill holes in raising an earthen *fortress/fort* → *plug/dam up*; *stop (up)* → *fill*; *be filled*.

[Full Kanji Etymology List]