険 is built from the 阝 (hill (left) / village (right)) and 僉 (all / together (in 検·険)) components.
It belongs to a phonetic family with 検, 験, 剣, and 倹 — they share the 僉 component and the reading ケン.
A common word using 険 is 危険 (きけん), meaning “danger, risk, hazard”.
Don't confuse it with 験, 検, 倹, and 剣 — 馬 test, 阝 steep, 木 examine, 亻 frugal
