限 - Adhere to the LIMITS

Readings & Meanings:

かぎ（る）

ゲン

limit

Common Usage:

限界

限りない

無限

制限速度

Examples:

彼の態度に我慢するにも限界がある。

限りなく広がる未来。

無限に広がる宇宙。

制限速度を守りましょう。

Translations:

There is a limit to his patience.

The future is limitlessly spreading out before us.

The universe spreads out infinitely.

Let's keep to the speed limit.

Radical:

阝 on the left means Kozato, piled earth.

On the right, we almost have "good," 良, but not quite. It's 艮, and Kanji Networks is a little unclear about it. KN says that 艮 is an indelible tattoo, whcih indicates adherence. However, I can't find info on 艮 itself.

At any rate, the Kozato radical (shorthand for 阜) makes us think of walled borders around a town, hence, limits.

References:

http://www.kanjinetworks.com/indices/radindex.html
http://www.thejapanesepage.com/node/kanji/ka.htm