What is BITCHING?

An argument with a friend today made me think of what we deem fit to call bitching and what are the things that don't come under that.
By this time I am sure you would have come across numerous occasions where you would have been bitching about somebody or someone would come to you and bitch about somebody or may be you are the person everyone is bitching about. But what exactly is it?
Lets google it. Amongst the top results were:

Offensive
a. A woman considered to be spiteful or overbearing.
b. A lewd woman.
c. A man considered to be weak or contemptible.
Slang A complaint.
Slang Something very unpleasant or difficult.

Its funny how everything written under the offensive category pertains to a woman. But I am cent percent sure that men bitch too! May be they don't call it by the same name but I am sure they do!

So what is it now?
Bitching - talking bad about someone in front of them or behind their back.
But I don't think this definition is apt as well. Well imagine a situation in when you go upto a friend a tell him/her about all the good things that happened to you in a day or about a really nice guy/girl who had helped you with some stuff in the day. You go to your friend and praise about them, right? But then why is the same thing termed as bitching if you go upto your friend and tell about a guy/girl who had been really mean to you in the day or something bad had happened to you because of that person. Why is it that this conversation is termed as bitching about that person?

In my opinion bitching is when you talk very negatively / even superficially / based on false assumptions / without completely knowing that person or his intentions + your own masala and then presenting it to the listener. Now that's what I call bitching! :D

Well know that you know my definition. Live a guilt free life. ;)