(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.