stealth

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of moving, proceeding, or acting in a covert way.
• noun The quality or characteristic of being furtive or covert.
• noun Obsolete The act of stealing.
• adjective Not disclosing one's true ideology, affiliations, or positions.
• adjective Having or providing the ability to prevent detection by radar.

from The Century Dictionary.

• noun The act of stealing; theft.
• noun A thing stolen.
• noun A secret or clandestine method or proceeding; means secretly employed to gain an object; surreptitious way or manner: used in a good or a bad sense.
• noun A secret going; a stolen or clandestine visit.

from the GNU version of the Collaborative International Dictionary of English.

• noun obsolete The act of stealing; theft.
• noun obsolete The thing stolen; stolen property.
• noun The bringing to pass anything in a secret or concealed manner; a secret procedure; a clandestine practice or action; -- in either a good or a bad sense.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable the attribute or characteristic of acting in secrecy, or in such a way that the actions are unnoticed or difficult to detect by others.
• noun archaic, countable an act of secrecy, especially one involving thievery

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun avoiding detection by moving carefully