What is the meaning of unfaithful?

adjective

• Not true to duty or obligation or promises.
  • usage: "an unfaithful lover"
• Having sexual relations with someone other than your husband or wife, or your boyfriend or girlfriend.
  • usage: "her husband was unfaithful"
• Having the character of, or characteristic of, a traitor.
  • usage: "the faithless Benedict Arnold"; "a lying traitorous insurrectionist"
  • synonyms: faithless, traitorous, treasonable, treasonous
• Not trustworthy.
  • usage: "an unfaithful reproduction"