Legal Dictionary


Definition of infidelity


    in- +‎ fidelity


infidelity (plural infidelities)

  1. Unfaithfulness in marriage or other moral obligation.
  2. Lack of religious belief.


  • (moral): betrayal
  • (religious): faithlessness


  • (moral): faithfulness
  • (moral): loyalty
  • (moral): fidelity

Related terms

  • (religious): infidel

Further reading

Infidelity is a violation of the mutually agreed-upon rules or boundaries of an intimate relationship, which constitutes a significant breach of faith or a betrayal of core shared values with which the integrity of the relationship is defined. In common use, it describes an act of unfaithfulness to one's husband, wife, or lover, whether sexual or non-sexual in nature.

There are two areas in a close relationship where infidelity mostly occurs: physical intimacy and emotional intimacy. Infidelity is not just about sex outside the relationship, but about trust, betrayal, lying and disloyalty.[1] What makes infidelity so painful is the fact that it involves someone deliberately using deception to violate established expectations within a relationship.

Sexual infidelity refers to sexual activity with someone other than the partner one is committed to. Sexual infidelity in marriage is called adultery, philandery or an affair and in other interpersonal relationships it may be called cheating. A man whose wife has committed adultery is referred to as a cuckold, while a woman whose husband has cheated on her is known as a cuckquean.

What constitutes an act of infidelity varies between and within cultures and depends also on the type of relationship that exists between people. Even within an open relationship, infidelity may arise if a partner to the relationship acts outside of the understood boundaries of the relationship.

Emotional Infidelity refers to emotional involvement with another person, which leads one's partner to channel emotional resources such as romantic love, time, and attention to someone else.[2]. With the association of multi-user dimensions the level of intimate involvement has extended from in-person involvement to online affairs.


  1. a b c d Jayson, Sharon (2008-11-17). "Getting reliable data on infidelity isn't easy". USA Today. Retrieved 2009-10-19.
  2. Close encounters: Communication in relationships.Guerrero , L.K. , Anderson, P.A. , & Afifi, W.A. (2007).Sage Publications.


  1. Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.


1.     lex situs
2.     AORO
3.     lex causae
4.     scienter
5.     adjudication order
6.     lex loci celebrationis
7.     Miranda warning
8.     quorum
9.     lex patriae
10.     appellant