Irish Luck - Doesn't Mean What You Think It Means

It's one of those expressions like "familiarity breeds contempts" and "lion's share" that no one uses correctly anymore.

From time to time somebody even observes: "Why would you want luck o' the Irish? Historically the Irish have pretty terrible luck."

That, friends, is actually key to the saying.

Correctly, when someone talks of Irish luck or luck o' the Irish, it doesn't mean luck. 

As one 1838 book put it, "Irish luck -- which means anything but chance."

In other words, if you say someone got something through Irish luck, it means he got it through something other than being lucky. It might mean hard work, it might mean bribery, it might mean trickery, but not luck. Anything but luck is Irish luck.