{μοιχάω} (verb 2nd sg aor subj act ) "Do...commit adultery" is moichao, which means "commit adultery with a woman" or "to debauch her." There are two versions of this verb are used. This is the rarer version used by Mark and once by Matthew. John never uses any form of this word. Both versions are common in Greek. The biblical translations conflate them, so I have to check the Greek to see which is used. --  -- The word translated as "commit adultery" means to"corrupt a woman." In the Greek Old Testament, this word was used to refer to being faithless to the Divine. Jesus uses the word translated as "adultery" most often to describe the faithlessness of divorcing a spouse. The broader concept of the time was that "adultery" is anything that is corrupting, as we might say "adulterating." However, the concept is more specific than that. It focuses on activities that violate vows. The central vow in human relationships is the marriage vow.  Violating such vows betrays the one to whom the vow is made and corrupts the person breaking it. In Jewish law, unmarried women could not commit adultery. A vow is required. Using this idea, Jesus connects adultery with the destruction of trust, faithlessness, rather than sex. Therefore, the word is also used to refer to idolatry. Idolatry violates a vow to God.