Merriam-Webster Collegiate Dictionary - stealth

 I. noun  Etymology: Middle English stelthe; akin to Old English stelan to steal  Date: 13th century  1.  a. archaic theft  b. obsolete something stolen  2. the act or action of proceeding furtively, secretly, or imperceptibly the state moves by ~ to gather information — Nat Hentoff  3. the state of being furtive or unobtrusive  4. an aircraft-design characteristic consisting of oblique angular construction and avoidance of vertical surfaces that is intended to produce a very weak radar return  II. adjective  Date: 1987 intended not to attract attention ; ~y a ~ campaign