What is the meaning of Faithful?

Loyal; adhering firmly to person or cause.

Having faith.

Reliable; worthy of trust.

Consistent with reality.

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

Injective in specific contexts, e.g. of representations in representation or functors in category theory.

Whose annihilator is zero.

The practicing members of a religion or followers of a cause.

Someone or something that is faithful or reliable.

Source: wiktionary.org