faithful

Marked by fidelity to an original.

“a faithful copy of the portrait”

“a faithful rendering of the observed facts”

Not having sexual relations with anyone except your husband or wife, or your boyfriend or girlfriend.

“he remained faithful to his wife”

Steadfast in affection or allegiance.

“years of faithful service”

“faithful employees”

A group of people who adhere to a common faith and habitually attend a given church.

Any loyal and steadfast following.