Come to think of it - cheating. How do you express cheating in your language? And what kind of cheating?
In greek there are cases in which we express cheating as stealing (though no actual stealing is implied). When playing cards, you can accuse someone of stealing, for example, meaning cheating, even if no money is involved.
When it's a board game, or children playing, you can say they are doing ζαβολιές (zavolies), which translated back into english would be, erm, something like they are being mischievous?
Cheating in a relationship is απατάω (apatao), almost the same as εξαπατάω (exapatao), meaning to con, to deceive.
So cheating is definitely one word that can't be translated to one simple word, at least in greek
