undetectable

adj

1. Unable to be detected; not detectable.

   “In these days of “rolled” gold, electro-plate, and undetectable pearls, it is curious that almost the only honest Ersatz material known to the goldsmith's art should be utterly forgotten.”

   “A trial of scar may be justified in a woman with a previous cesarean section who is currently on HAART, has an undetectable virus and spontaneously goes into labor.”

   ““OK, so for a few weeks I've been working on a bit of a side project. I give you the Red Kriegtober.” “Um--” “Or the Red Octkrieger. I can't decide. It's a narco sub for transporting cocaine. It's totally undetectable by the Coast Guard. Thoughts?””

   “Some forms of data poisoning are undetectable. Attackers can insert adversarial noise into the training data, altering the training data in a way that is hidden to human observers.”