Casuist is a noun that refers to a person who uses clever but unsound reasoning.

The Latin word casus (KAH soose) means ‘case,’ and you could think of casuists as similar to lawyers, constantly working on a case. Here’s an example of our word of the day in use:

My daughter’s only ten and she’s already become something of a casuist. She managed to convince me and her mother that she shouldn’t eat carrots with dinner because she didn’t support the slaughter of innocent carrots.