From time to time, I hear people say that we shouldn't label ourselves or others. We are each unique beings and those nasty labels are rigid and confining. While there is certainly some truth to this assertion, communication would be near too impossible WITHOUT labels.
If you think about it, nouns are labels. A noun such as tree isn't the thing itself; it is a label for a kind of thing. If I write a post about the trees in the forest behind my house, you would get a general mental picture, but you wouldn't "see" the same "trees."
It is in this same vein that we use labels to define ourselves and others. When a person says, "I'm a Republican" or "I'm a Lutheran," it doesn't tell us each and every one of their own specific personal beliefs, but it does provide us with a generalized idea of where they are coming from.
In No Religion? 7 Types of Non-Believers, Valerie Tarico discusses 7 labels that non-religious people might use by with which to identify themselves.
Of this particular list, I would use atheist, skeptic and freethinker to identify my general beliefs to others. If you follow the link to read the article and Tarico's explanation of each label, which ones would you use to describe yourself (providing, of course, you see yourself as a "non-religious" person)?