'Unfaithful' in the Bible

that servant's Master will come on a day when he is not expecting Him and at an hour that he knows not of, and will punish him severely, and make him share the lot of the unfaithful.

For what if some Jews have proved unfaithful? Shall their faithlessness render God's faithfulness worthless?

Though I am not conscious of having been in any way unfaithful, yet I do not for that reason stand acquitted; but He whose scrutiny I must undergo is the Lord.

You unfaithful women, do you not know that friendship with the world means enmity to God? Therefore whoever is bent on being friendly with the world makes himself an enemy to God.

But as for cowards and the unfaithful, and the polluted, and murderers, fornicators, and those who practise magic or worship idols, and all liars--the portion allotted to them shall be in the Lake which burns with fire and sulphur. This is the Second Death."