Faithless, a.
1. Not believing; not giving credit. Be not faithless, but believing. John xx. 27.
2. Not believing on God or religion; specifically, not believing in the Christian religion. Shak.
3. Not observant of promises or covenants.
4. Not true to allegiance, duty, or vows; perfidious; trecherous; disloyal; not of true fidelity; inconstant, as a husband or a wife. A most unnatural and faithless service. Shak.
1 more senses
5. Serving to disappoint or deceive; delusive; unsatisfying. "Yonder faithless phantom." Goldsmith. -- Faith"less*ly, adv.Faith"less*ness, n.