1.Definition: marked by fidelity to an original
"A faithful copy of the portrait", "A faithful rendering of the observed facts"
2.Definition: not having sexual relations with anyone except your husband or wife, or your boyfriend or girlfriend
"He remained faithful to his wife"
3.Definition: 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"