Swinging or (rarely) partner swapping is a non-monogamous behavior, in which partners in a committed relationship engage in sexual activities with others as a recreational or social activity. Swinging can take place in a number of contexts, ranging from spontaneous sexual activity involving partner swapping at an informal gathering of friends to planned regular social meetings to "hooking up" with like-minded people at a swingers' club. The phenomenon of swinging, or at least its wider discussion and practice, is regarded by some as arising from the freer attitudes to sexual activity after the sexual revolution of the 1960s, the invention and availability of the contraceptive pill and the emergence of treatments for many of the sexually transmitted diseases that were known at that time.
The swinger community sometimes refers to itself as "the lifestyle", or as "the alternative lifestyle". The term "swinging" is more commonly used instead of the older term wife swapping which has been criticized for being androcentric, for presuming that the partners are a married heterosexual couple, and for presuming that it is the male who is in control of the sexual activities. Additionally, the term "wife swapping" or "partner swapping" is criticized for not accurately describing the full range of sexual activities in which both singles or couples may engage, which is not limited to conventional sex with a person other than their regular sex partner. Other terms sometimes encountered are wife sharing, partner sharing and wife lending, which describe similar concepts, usually in sociological or anthropological research.
It is noted that not all swingers participate, approve of, or understands BDSM, nor wish to, though there is often cultural overalap.