"IF"

Remember the movie 300 ? It was about sparta. There was a district in sparta in ancient times, named laconia  whose inhibitants were famous for their brevity of speech. Once, Philip of macedon, threatened them with "if i enter laconia, i will raze sparta to the gorund" . The spartans' reply was  "if ".  Pretty laconic, right ?

So when you Express much in few words, after the manner of the Laconians or Spartans; brief and pithy; brusque; epigrammatic; you are being laconic.