Lieut. is a written short form of lieutenant — an officer rank in the army, navy, or air force. You see it on letters, nameplates, and older lists; you do not say “Lieut” out loud as a new word. When you read it, you say the full word lieutenant. Though actually most writing now uses Lt. instead; Lieut. looks a little old. The exact step on the ladder (above whom, below whom) depends on the country and the service, but the job is a junior officer, not the person in overall command. British speakers often start lieutenant with a “lef-” sound; American speakers usually start it with “loo-.” Neither group reads the abbreviation as “loot.”