Weakness

I am having a little trouble with my English, so I want some people to help me out. This word, weakness. What does it mean? Is it just an opposite of strength? If so, what is strength?
Is beating up someone strength? If a person reacts angrily to every minor offence, is that a show of strength? Is creating a scene in public, strength?
Laughing at the face of minor botherations, just because you have seen worse, does that define weakness?
No, this is not a tirade against any particular person. These are just a few questions which arose in my mind after today. And yes, I am still looking for an explanation.