What does the word religious mean in the dictionary?

Taken from the Collins Consice

1. of, relating to, or concerned with religion.

2. a. pious; devout; godly. b.(as collective n.;preceded by the): the religious.

3. appropriate to or in accordance with the principles of a religion.

4. scrupulous, exact, or conscientious.

5. Christianity. of or relating to a way of life dedicated to religion and defined by a monastic rule. ~n.

6. Christianity. a monk or nun. -re'ligiously adv. -religiousness n.