急
キュウ, いそ.ぐ, いそ.ぎ

hurry, emergency, sudden, steep

JLPT4 G3 S9 F309

The relevant seal inscription form shows 急 to have originally consisted of 及# (press on) + 心 heart/emotions → feelings of being pressed upon → *rush*; *hurry*; *hasten* → *sudden*; *emergency*; *steep*.

[Full Kanji Etymology List]