険 (Kanji for steep / risky)

Onyomi

KEN

It's risky to build a town on such a steep hill.

けわ*しい

a steep hill, or a very grim situation (but mostly a steep hill).
★★☆☆☆

冒険(ぼうけん)	adventure ★★★☆☆ 冒 (dare) + 険 (steep / risky) = 冒険 (adventure)
保険(ほけん)	insurance ★★★☆☆ 保 (guarantee/maintain ) + 険 (steep / risky) = 保険 (insurance)
危険(きけん) な	risky, unsafe ★★☆☆☆ 危 (dangerous) + 険 (steep / risky) = 危険 (risky, unsafe)

	Meaning	Hint	Radical
除	exclude	EXCESS	余
険	steep / risky	RISK

Japanese exclude the EXCESS foreigners because the RISK is too steep.