Laconic phrase

A laconic phrase or laconism is a concise or terse statement, especially a blunt and elliptical rejoinder. It is named after Laconia, the region of Greece including the city of Sparta, whose ancient inhabitants had a reputation for verbal austerity and were famous for their blunt and often pithy remarks.
Uses.
A laconic phrase may be used for efficiency (as during military training and operations), for emphasis, for philosophical reasons (especially among thinkers who believe in minimalism, such as Stoics), or to deflate a pompous interlocutor.
A prominent example involves Philip II of Macedon. After invading southern Greece and receiving the submission of other key city-states, he turned his attention to Sparta and asked menacingly whether he should come as friend or foe. The reply was ""Neither"."
Losing patience, he sent the message: 
If I invade Laconia, I shall turn you out. 
The Spartan ephors again replied with a single word: 
"If." 
Philip proceeded to invade Laconia, devastate the northern half of it and eject the Spartans from various parts.
In humor.
The Spartans were especially famous for their dry, understated wit, which is now known as "laconic humor". This can be contrasted with the "Attic salt" or "Attic wit" the refined, poignant, delicate humour of Sparta's chief rival, Athens.
Various groups in more recent history also have a reputation for laconic humor: Icelanders in the sagas, and in the Anglophone world, Australians ("cf." Australian humor), American cowboys, New Englanders and people from the North of England.
History.
Spartans paid less attention than other ancient Greeks to the development of education, arts, and literature. Some view this as having contributed to the characteristically blunt Laconian speech. However, Socrates, in Plato's dialogue "Protagoras", appears to reject the idea that Spartans' economy with words was simply a consequence of poor literary education: "... they conceal their wisdom, and pretend to be blockheads, so that they may seem to be superior only because of their prowess in battle ... This is how you may know that I am speaking the truth and that the Spartans are the best educated in philosophy and speaking: if you talk to any ordinary Spartan, he seems to be stupid, but eventually, like an expert marksman, he shoots in some brief remark that proves you to be only a child". Socrates was known to have admired Spartan laws, as did many other Athenians, but modern scholars have doubted the seriousness of his attribution of a secret love of philosophy to Spartans. Still, the Spartans Myson of Chenae and Chilon of Sparta have traditionally been counted among the Seven Sages of Greece; both were famous for many laconic sayings.
In general, however, Spartans were expected to be men of few words, to hold rhetoric in disdain, and to stick to the point. Loquacity was considered frivolous and unbecoming of sensible, down-to-earth Spartan warriors. A Spartan youth was reportedly liable to have his thumb bitten as punishment for too verbose a response to a teacher's question.
External links.
 (additional examples of laconic phrases)