undetectable
un·de·tec·table
adjective
2.
- “the transition was almost indiscernible”
- “an almost insensible change”
Origin
From un- + detectable.
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.