Rhathymia is a noun that refers to a state of being carefree or light-hearted.

The Greek word rathymos (RATH ee mose) means ‘easy-going’ or ‘carefree.’ After spending several light-hearted centuries in English, our word of the day still retains the same meaning it did in its homeland. Here’s an example:

Phil is ordinarily a pretty easy-going guy, but when his favorite Tai restaurant permanently closed, his rhathymia disappeared immediately.