1A permanent or long-term exchange of wives between married couples, especially for the purpose of remarriage.
2A temporary exchange of wives or sexual partners between couples for the purpose of engaging in sexual activity.
Mid 19th century; earliest use found in Sullivan (Indiana) Democrat. From wife + swap.
no object To exchange wives or sexual partners for the purpose of engaging in sexual activity; to engage in wife-swapping.
1960s; earliest use found in Logansport (Indiana) Pharos-Tribune. From wife + swap, after wife-swap, wife-swapping.