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

Concise Bible Dictionary:

The name given in scripture to the class of persons who have not faith in the divine revelation of the gospel (Luke 12:46; 1 Cor. 6:6; 1 Cor. 14:23; 2 Cor. 6:14). The word is translated “infidel” (2 Cor. 6:15; 1 Tim. 5:8); and “faithless” (Matt. 17:17; Mark 9:19; Luke 9:41; John 20:27).

Strong’s Dictionary of Greek Words:

Number:

571 (find all occurrences in KJV Bible)

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)