a. 1. Not believing; not giving credit. [ 1913 Webster ]
Be not faithless, but believing. John xx. 27. [ 1913 Webster ]
2. Not believing on God or religion; specifically, not believing in the Christian religion. Shak. [ 1913 Webster ]
3. Not observant of promises or covenants. [ 1913 Webster ]
4. Not true to allegiance, duty, or vows; perfidious; trecherous; disloyal; not of true fidelity; inconstant, as a husband or a wife. [ 1913 Webster ]
A most unnatural and faithless service. Shak. [ 1913 Webster ]
5. Serving to disappoint or deceive; delusive; unsatisfying. “Yonder faithless phantom.” Goldsmith.
-- Faith"less*ly, adv.Faith"less*ness, n. [ 1913 Webster ]