Mordant

WORD OF THE DAY

mordant / adjective / MOR-dunt

Definition
1a: biting and caustic in thought, manner, or style
1b: incisive
2: acting as a mordant (as in dyeing)
3: burning, pungent

Examples
"When Clementine tried to tell him that the result might well be a blessing in disguise, [Winston Churchill] maintained his normal standards of mordant wit by replying that 'at the moment it's certainly very well disguised.'"
— Roy Jenkins, Churchill: A Biography, 2001

"For Lucas Hedges, acting is a kind of ongoing education in how to live in the world. Take his performance as a troubled and mordant young man who's just lost his father in Kenneth Lonergan's gorgeously melancholy 2016 film Manchester by the Sea, which Hedges calls 'the most formative role of my life.'"
— Adam Green, Vogue, 24 Sept. 2018

Did You Know?
The etymology of mordant certainly has some bite to it. That word, which came to modern English through Middle French, ultimately derives from the Latin verb mordēre, which means "to bite."
In modern parlance, mordant usually suggests a wit that is used with deadly effectiveness. Mordēre puts the bite into other English terms, too. For instance, that root gave us the tasty morsel ("a tiny bite").
But nibble too many of those and you'll likely be hit by another mordēre derivative: remorse ("guilt for past wrongs"), which comes from Latin remordēre, meaning "to bite again."