that believeth not, faithless, incredible thing, infidel, unbeliever(-ing)

Strong’s Dictionary of Greek Words:

Greek:
ἄπιστος
Transliteration:
apistos
Phonic:
ap’-is-tos
Meaning:
from 1 (as a negative particle) and 4103; (actively) disbelieving, i.e. without Christian faith (specially, a heathen); (passively) untrustworthy (person), or incredible (thing)
KJV Usage:
that believeth not, faithless, incredible thing, infidel, unbeliever(-ing)