believer

A believer is someone who trusts or has faith in something, such as a person, idea, or higher power.

You often hear people talk about their religious beliefs, but being a believer can also mean trusting a particular way of life or philosophy. For instance, some people are believers in the importance of living a simple and self-sufficient lifestyle, while others believe in the benefits of technology and modern convenience. Being a strong believer usually means you're passionate about your convictions and willing to stand up for them.