What is a Worldview?
A worldview is how you look at the world, how you think it operates, why things happen the way they do, what your purpose is.
Logically your behaviors, your actions, your motivations, should be consistent with your worldview. For example, a worldview of atheism, which is a belief that God does not exist, explains the creation of the universe and of life as randomness acting over a very long time. In such a worldview, it is easy to adopt a worldview that people can have no purpose, for it is by accident that people even exist. Many atheists claim that people create their own purpose. But, if you think about it, an artificial purpose is not a real one, and can have no real meaning. Additionally, if we did just evolve by accident, then our thoughts (including any thoughts we have about purpose) are meaningless, in that they are just the result of chemical, electrical, and quantum processes occurring within a statistical aberration (for evolution says that we are nothing more than statistical aberrations). So, any time atheists act as if their actions matter, their behavior is not consistent with their worldview. When you think about this some more, you will probably conclude that it is a good thing that many atheists do not act in a manner consistent with their worldview. Many atheists adopt a worldview of secular humanism, which acknowledges the value of human life and encourages people to help each other "because this world is all there is, so we should make the most of it." Personally, I don't understand how this can be considered to be in line with their assumptions, but I really don't care, because I would prefer to know an atheist who cares about people than one who does not.
Another example is the Christian worldview. Clearly, the behaviors of Christians should be consistent with the teachings of Jesus Christ, or their behaviors are not consistent with their worldview. People who hold to the Christian worldview should act as if everything that they do matters. And, when you think about this some more, you will probably conclude that it is not a good thing that many Christians do not act in a manner consistent with their worldview.
And a final example: if you believe in karma, as millions do, how do you translate it into action in your own life? If you know of someone who is suffering and you have the power to help them, do you not help them because you think suffering is their karma? Or do you help them, because it is your karma? It's not an easy question to address (although I am sure it is treated properly in some wisdom literature), but it is an important one.
No doubt many people could do a better job of explaining the concept of a worldview, but this brief summary should give you a picture of what a world view is, and of what it means.