Why try to define virtue?

We've been considering the ideas of what virtue is, how people have thought of achieving it, and many other aspects of the word in class. When you look virtue up on dictionary.com, it says, "moral excellence; goodness; righteousness." Therefor you must have excellent morals to be virtuous. Those words mean different things to all of us. Do we not all have different morals, different perspectives on what's good what's and right? Most people would agree. If the substance of the words that we use to define virtue fluctuate within every different person and situation, why try and give it a definition? We can give words like virtue, god, faith, and knowledge concrete descriptions in the dictionary, but if the words we use to define these terms are always disputed and rarely agreed upon, why give them definitions in the first place?

moral excellence; goodness; righteousness." Therefor you must have excellent morals to be virtuous. Those words mean different things to all of us. Do we not all have different morals, different perspectives on what's good what's and right? Most people would agree. If the substance of the words that we use to define virtue fluctuate within every different person and situation, why try and give it a definition? We can give words like virtue, god, faith, and knowledge concrete descriptions in the dictionary, but if the words we use to define these terms are always disputed and rarely agreed upon, why give them definitions in the first place?