Inequality
Unequal
noun, な adjective, の adjective
When something is not equal is of course unequal. It's an inequality. You'll usually see this word in technical contexts like math and engineering, but it does pop up in more general formal writing, too.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
これは上から見ると不等辺三角形になるようにデザインされています。
This is designed to form an scalene triangle when viewed from above.
この時、以下の不等式が成り立ちます。
At this time, the following inequality holds.
この車は、トルクが前41：後59で不等配分されるようになっています。
The car is designed to distribute torque unequally at 41:59 between the front and the rear.