(noun)
a type of aircraft design characterized by slanted surfaces and angles and no vertical surfaces, which makes them difficult to detect by radar technology;
e.g. An enemy stealth aircraft flew over the city.
(adjective)
intended to be secretive or unobtrusive, not attracting attention, i.e. stealthy;
e.g. I didn't hear his stealth approach, so I was surprised when he appeared behind me.
(adjective)
in medical usage, caused by or relating to infectious individuals who either do not show symptoms or who are too early in their infection to show symptoms;
e.g. The stealth transmission of the illness made it difficult to control.