Faithless
Webster's Dictionary [1]
(1): ( a.) Not true to allegiance, duty, or vows; perfidious; trecherous; disloyal; not of true fidelity; inconstant, as a husband or a wife.
(2): ( a.) Serving to disappoint or deceive; delusive; unsatisfying.
(3): ( a.) Not believing; not giving credit.
(4): ( a.) Not believing on God or religion; specifically, not believing in the Christian religion.
(5): ( a.) Not observant of promises or covenants.
King James Dictionary [2]
FA'ITHLESS, a.
1. Without belief in the revealed truths of religion unbelieving.
O faithless generation. Math 18.
2. Not believing not giving credit to. 3. Not adhering to allegiance or duty disloyal perfidious treacherous as a faithless subject. 4. Not true to a master or employer neglectful as a faithless servant. 5. Not true to the marriage covenant false as a faithless husband or wife. 6. Not observant of promises. 7. Deceptive.
Yonder faithless phantom.
Hastings' Dictionary of the Bible [3]
Faithless . Wherever this word occurs in AV [Note: Authorized Version.] , it means, not untrustworthy, but unbelieving, just as in the Merchant of Venice Shylock is called ‘a faithless Jew,’ simply because he was an unbeliever in Christ.
International Standard Bible Encyclopedia [4]
fāth´les ἄπιστος ápistos Matthew 17:17 Mark 9:19 Luke 9:41 John 20:27 2 Timothy 2:13 1 Corinthians 7:12-15 1 Corinthians 10:27 1 Corinthians 14:22 1 Corinthians 14:24 Titus 1:15 Luke 12:46 apistos Revelation 21:8