Merriam-Webster's Word of the Day for August 17, 2023 is:

volatile • \VAH-luh-tul\  • adjective

Volatile has several closely related meanings, including “subject to rapid or unexpected change,” “having or showing extreme or sudden changes of emotion,” and “likely to become dangerous or out of control.”

// Our financial advisor cautioned us to be conservative with our investments while the stock market was still volatile.

// One classic trope of war movies is the drill sergeant with a volatile temper, always ready to yell at recruits for the slightest infraction of the rules.

// The protests are increasing, creating a volatile situation in the capital.

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Examples:

“This smart … novel has more secrets than you could successfully hide from your Sunday school teacher. Set in a beautifully evoked Cape Cod, in politically volatile 2016, the novel centers on the Gardner family. There's Adam, the brilliant, but erratic, father; Ken, his Babbitt-like real estate developer son; and Abby, his artist daughter, whom he considers ‘a special snowflake of the highest order.’” — Jeffrey Ann Goudie, The Boston Globe, 23 June 2023

Did you know?

Volatile was originally for the birds—quite literally. Back in the 14th century, the word was a noun and volatiles were birds (especially wild fowl) or other winged creatures, such as butterflies. That's not as flighty as it sounds. Volatile traces back to the Latin verb volare, which means “to fly.” By the end of the 16th century, people were using volatile as an adjective to describe meal ground so fine and light that it could easily “fly” or be blown about. Soon after, the adjective was extended to creatures that were capable of flying (as in “volatile insects”), later to vapors and gases, and by the early 17th century, to individuals or things as prone to sudden change as some gaseous substances. In recent years, volatile has alighted in economic, political, and technical contexts far flown from its avian origins.