Merriam-Webster's Word of the Day for September 3, 2026 is "recalcitrant." This formal adjective describes someone who stubbornly disobeys rules or orders. It can also apply to things that are difficult to manage or operate. For instance, parents may need tricks to coax a recalcitrant toddler into cooperating. An example illustrates a driver accumulating many speeding tickets, showing their recalcitrant nature. When faced with a command, a recalcitrant individual or animal resists firmly. This resistance can be understood through the word's etymology. "Recalcitrant" traces back to the Latin word "calx," meaning "heel." From "calx," the Latin verb "calcitrare" (to kick) was formed. Subsequently, "recalcitrare" emerged, meaning "to kick back." In Late Latin, this figurative meaning of stubborn disobedience led to the English adjective. Thus, "recalcitrant" is used for those who defiantly refuse to yield.