A short term feeling of having lots of energy, one who is hyper usually does crazy/stupid things and laughs a lot. Often called a "natural high" and is caused by mutliple things: friends, sugar, lack of sleep, night, etc

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

When you cant concentrate on anything and you feel like bouncing off the walls...natural high usually...well...sugar

The first syllable is "high" and the second is "purr", therefore to be hyper is to be like a drugged cat. Yes. Really.

Extreme to the point of contrapositional self-reference in the next cultural, mathematical, or metaphysical paradigm

In the furry fandom (and most likely other places with sexual minorities), hyper means to be excessively endowed to the point of ridiculous and unrealistic proportions. This can also be combined or replaced with the muscle fetish to mean unrealistically gigantic muscular proportions.

when you eat a lot of sugar and jump around everywhere yelling four square and raawk and telling your teachers to shut up