Quote from Roflorz;1287485:
Nor is making an "illegal move" in chess.
Laws don't always have to do with governments or countries.
Well, the definition of the word "law" implies (and is stated by multiple dictionaries) to specifically refer to a body of government at some level (national, state, county, town).
But you're right that "illegal" doesn't always mean breaking an actual law as it can mean breaking
a rule in a game or something... but the connotations of the word "illegal" outside of a sporting event usually mean breaking the law, so I'm always sure to point out that it's not breaking the law.
('Cause a lot of people literally think that game companies have government-level say in what you can and cannot do when their products are involved, which is BS.)