faithful

steadfast in affection or allegiance

• “years of faithful service”
• “faithful employees”
• “we do not doubt that England has a faithful patriot in the Lord Chancellor”

marked by fidelity to an original

• “a close translation”
• “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”

any loyal and steadfast following

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