Texte d'origine - Anglais - Swinger

Did this come up in a dance context or a sexual context? :P

it came up in a conversation about somebody's marital status...

ooh...
Well, everytime I heard of the word, it basically meant couples meeting other couples to swap sexual partners, for example in "swing clubs". Apparently, "swingers" give the activity a much broader definition, though. You might want to check http://en.wikipedia.org/wiki/Swinging to learn more.
In French, I guess it's a variant of "echangisme". I can't speak Greek, but with this context, I'm sure someone will be able to help you with the translation

Yes; I agree with CocoT - it's someone who regularly swaps spouses with other couples. They have swinger clubs and swinger parties and so forth.

thanks a lot!!