Answer:
A devout Catholic is typically someone who goes to church at least once per week, prays regularly, goes to confession regularly, generally follows the moral teachings of the church, and by their example encourages other Catholics to do so as well. However, anyone who is baptized by a Catholic priest is considered by the Church to be Catholic whether or not they do any of those things. I know many Catholics personally who attend services at Episcopal, Lutheran, and various other Christian churches, or who do not go to church at all, and they are all still considered by the Catholic Church to be Catholic.