危 - Danger! Coiled Spring Inside

Readings & Meanings:

あぶ（−ない）

キ

dangerous, unsafe, unsteady

あや（−うい）（−ぶむ）　

to fear, to mistrust

Common Usage:

危ない

危険

危ぶむ

Examples:

気を付けろ！危ない！

危険！近いよるな！

現首相の健康を危ぶむ声もある。

Translations:

Be careful! Danger! (commonly spoken)

Danger! Do not come close! (This is not spoken Japanese; this would be found on a sign in front of a pond or a construction site.)

Some people are skeptical about the current prime minister's health.

Bonus:

I just learned that the "exclamation mark" in Japanese is called "びっくりマーク"!

References:

http://www.jlptstudy.com/2/index.html
http://www.thejapanesepage.com/kanji/kanji/a.htm