Definition of "faithful" in English

adjective

1. Loyal; adhering firmly to person or cause.

   • My dog is very faithful: he doesn't like to be petted by anybody else.

2. Having faith.

3. Reliable; worthy of trust.

   • My servant is very faithful.

4. Consistent with reality.

   • I would consider that a very faithful reproduction.

5. Engaging in sexual relations only with one's spouse or long-term sexual partner.

   • They had been faithful to each other all of their married life.

6. (mathematics) Injective in specific contexts, e.g. of representations in representation or functors in category theory.

7. (ring theory) Of a module, whose annihilator is zero.

noun

1. (in the plural) The practicing members of a religion or followers of a cause.

   • The faithful pray five times a day.

2. Someone or something that is faithful or reliable.