What does recalcitrant (refractory) mean and Where does the word “recalcitrant” come from?

Sometimes a stubborn horse or mule is content to let fly a few kicks without doing much damage, and let it go at that, but at other times he does not stop until he has broken up the cart to which he is hitched or has injured the driver.

On the first occasion the animal is most fittingly described as recalcitrant, which literally means “kicking back,” from Latin re, back, and calcitro (from calx, heel), to kick.

He may, of course, do damage.

A refractory animal or person, however, if the word is taken literally, is not content with being obstinate or stubborn; he breaks something.

The word, from Latin refractarius, is derived from refringo, to break up.