What is the meaning of faithful?

noun

• Any loyal and steadfast following.
• A group of people who adhere to a common faith and habitually attend a given church.
  • synonyms: congregation, fold

adjective

• Steadfast in affection or allegiance.
  • usage: "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.
  • usage: "a close translation"; "a faithful copy of the portrait"; "a faithful rendering of the observed facts"
  • synonyms: close
• Not having sexual relations with anyone except your husband or wife, or your boyfriend or girlfriend.
  • usage: "he remained faithful to his wife"