infidelity

/ˌˈɪnfəˌˈdɛlədi/

/ɪnfɪˈdɛlɪti/

Other forms: infidelities

Someone guilty of infidelity is cheating on a spouse or romantic partner. A common cause of divorce and heartbreak is infidelity.

Fidel means "faithful" or "loyal." Tack on the prefix in, which means "not," and you've got yourself infidelity — the act of being unfaithful. The word can also be used to refer to someone's religious beliefs. Run angrily through a church and claim that God doesn't exist, and your fellow churchgoers will think you lack faith, or that you are guilty of infidelity.

Definitions of infidelity

1. noun

   the quality of being unfaithful
   synonyms: unfaithfulness

   antonyms:

   fidelity

   the quality of being faithful

   types:

   faithlessness, falseness, fickleness, inconstancy

   unfaithfulness by virtue of being unreliable or treacherous

   disloyalty

   the quality of being disloyal

   disaffection

   disloyalty to the government or to established authority

   subversiveness, traitorousness, treason

   disloyalty by virtue of subversive behavior

   perfidiousness, perfidy, treachery

   betrayal of a trust

   type of:

   quality

   an essential and distinguishing attribute of something or someone