unreachable

adj

1. (not-comparable)Unable to be reached; impossible to attain.

   “[…] read-only attribute that lists the unreachable but uncollectable objects.”

noun

1. A person or thing that cannot be reached.

   ““Brands want to be in front of this audience,” Ms. Bamford said. “Reaching these unreachables, these cord-cutters who don’t want to be fed an ad, is a huge concern.””