Best .

Best Friend: {noun.}

Partner. Treasure. Counter-part. Incomparable.

Feeling complete trust that no matter what is uttered, no matter what is shared, no matter how hard...
they will listen. 

They understand it. They value and guard it.

They are someone who brings you up when you are down. They are someone who supports: you, your decisions, your likes, and not only encourages you to follow them... but helps you get there.
Someone who often understands you a bit more than yourself.

They enjoy you at your best, and never fail to help you at your worst.

They are someone who intuitively knows when to ask you if you need to talk, need a glass of wine, need a hug, or simply need to cry. They help you by reaching for your hand, and end up touching your heart instead.

When you worry, they give you hope. When you are dark, they give you light. When you are weak, they make you strong.

Most importantly, a best friend is someone that you can do anything, or absolutely nothing with... and the company is more than enough.