Apistia is a Greek word that means "lack of faith" or "infidelity."
While the word apistia originally refers to a lack of faith in a deity, it has been appropriated to refer to the type of infidelity a person shows when they cheat on a spouse.
In modern parlance, apistia specifically refers to the infidelity a person can show within their marriage. This faithlessness may involve engaging in an emotional affair or a physical one. Sex may or may not occur.
What constitutes apistia will vary from couple to couple, depending on whether a couple is monogamous or polyamorous, and what each couple believes constitutes cheating. For example, one couple may feel intercourse must occur for there to be apistia, while another may believe online flirting constitutes a breach of trust.
As marriage is considered to be a sacred institution, apistia is still seen as a sexual taboo.
