This seems like a nice word for the middle of summer, doesn’t it? We know it as meaning “lazy, languid.” Not always a good thing, but on a summer day, you might be inclined to give it less negative connotation, right?
This word has a fun history, though! It dates to the 1700s but is inspired by an expression of centuries gone by. Namely, when someone wanted to express regret for a failure, they would say “Alack the day!” Which is more or less saying they’re sorry that day happened. (I’ve had a few of those…)
Well, this eventually became the word lackaday. And if you used this word too often, you came to be known as lackadaisical.
It’s worth noting that lax is a completely different word with a different history, though it’s thought that the similar sound may have influenced our modern meaning of the lackadaisical a bit.