adultery

 
Pronunciation: /əˈdʌlt(ə)ri/

noun

[mass noun]
  • voluntary sexual intercourse between a married person and a person who is not their spouse: she was committing adultery with a much younger man

Origin:

late 15th century: from the obsolete noun adulter, from Latin adulter 'adulterer', replacing an earlier form avoutrie, from Old French avouterie