Not faithful; not observant of promises, vows,
allegiance, or duty; violating trust or confidence; treacherous;
perfidious; as, an unfaithful subject; an unfaithful agent or servant.
- Not true to ones sexual partner.
- One of Rihannas song.
Betraying your partner, disrespecting their trust. Being disloyal and not being honest. Cheating.
* These videos are coming directly from Youtube, they may or may not be most relevant to the word "Unfaithful"