I wouldn't

The environment, flora and fauna

The action of physical, chemical and biological forces on an environment.

Maybe...

Someones personality, such as "It's not her nature to lie".

I think a dictionary would give you a better definition than I.

Nature the open air and wild animals

...uh, a good example would be that it's in Wolf's (a.k.a. Tillicus, Darkshadowseeker, Teatree, bcollins, Kate and etc...) nature to correct such surveys as this one. Obviously, she ain't here to do so...

Let's rejoice!

that which is not man-made

The true characterization of something, what it is at its core.

The birds and the bees

*Sings* "In the jungle, the mighty jungle"...

Naked? Natural! Mother!

"Nature" is something that didn't even exist as a concept until the industrial revolution. Essentially, it means that which is not man or of man.

Things and environments that come from the Earth on its own. Not man made.

I'll have to look it up. But since I won't....nature is without unnatural.

What was on this planet before we decimated it. Small patches left if you look hard enough.

Being that of a natural state.

Yes, the dictionary would give a better definition. In fact, it would give you THE definition. This person wants to know what YOUR definition would be.