Laconic
Etymology
From Greek Lakonikos, "of Laconia," the region around Sparta. The Spartans were famous for brutal brevity: when a rival warned, "If I enter Laconia, I will raze it," they reportedly replied with a single word — "If." Their homeland’s name became the word for that terseness.
adjective · /luh-KON-ik/
Using very few words; terse to the point of dryness.
What it names
A style of speech that says more by saying less — restraint that can read as confidence or coolness.
Example
Asked how the meeting went, he gave a laconic "Fine" and left it there.
Related idea
Terse is neutral; laconic carries a hint of style, even attitude.