The English word godless is used about a dozen times in the Old Testament in the modern versions. The word literally means “without god.” The Merriam-Webster Dictionary defines godless as “not acknowledging a deity or divine law.” The godless have no respect for God; their thoughts and words are profane; they act in impious and wicked ways.
The Old Testament gives several details about the godless person. We find that the godless shall not have an audience with God (Job 13:16). Isaiah speaks of judgment coming upon Israel, who had become godless (Isaiah 33:14), at the hands of a godless nation (Isaiah 10:6).
In the New Testament, the word godless appears four times in the New International Version and the New American Standard Bible, whereas the English Standard Version translates the same Greek word three times as “irreverent” and once as “unholy.” The first three occurrences in the New Testament refer to godless speech (chatter, babble, and myths) that should be avoided (1 Timothy 4:7; 6:20; 2 Timothy 2:16). The final occurrence refers to Esau as a godless (or unholy) person who showed great disrespect for God in selling his birthright (Hebrews 12:16).
Taking all the biblical evidence into account, the term godless seems to describe someone or something that does not honor the One True God. In the Old Testament, godlessness manifests itself primarily in two ways. First, there are those like the nations who surrounded Israel; they may have been very religious, but they did not know the One True God. Then there are those within Israel who should have known God but acted as if they did not, so they were godless as well. (This may be the reason that the KJV translates the Hebrew word as “hypocrite”—even though they had intellectual knowledge of the One True God, they did not act on that knowledge.)
In the New Testament, godlessness is closely associated with irreverence. Godless usually describes speech that dishonors, makes light of, or even mocks the serious things of God. Godless people naturally speak in godless ways. The believer must avoid all kinds of godless speech and attitudes.
The godless person is not a person who has no god, for everyone has gods, including the atheist. A god is simply that which a person elevates to the position of greatest importance and significance. For some people this is the One True God or some pagan god, and for others it may be family, wealth, prestige, scientific materialism, or personal autonomy. Everyone has gods, even the godless, but only believers in Christ know and revere the One True God as He has revealed Himself in Scripture—Father, Son, and Holy Spirit.