noun, na-adjective
steepness; steep place
Refers to a steep geographical feature or the quality of being steep. Often used in literary or descriptive contexts.
この山道は険が厳しい。
This mountain path is very steep.
その崖は険を極める。
That cliff is extremely steep.
noun, na-adjective
Describes a stern, severe, or sharp expression or manner of speaking. The kanji 険 is most common, but 権 or 慳 may appear in older texts.
彼の険のある目つきに、思わずたじろいだ。
I flinched at his harsh glare.
険を含んだ口調で注意された。
I was warned in a sharp tone.
Common i-adjective meaning 'steep' or 'severe'; 険 is a more literary noun/adjectival noun form.
The kanji 険 originally depicts a steep, dangerous place. The extended sense of 'harsh' or 'sharp' likely derives from the idea of a severe, forbidding appearance.