- Not distinguishable; not capable of being perceived, known, or discriminated as separate and distinct
- Any sufficiently advanced technology is indistinguishable from magic — Arthur C. Clarke 
- Not capable of being perceived or known.
- (not capable of being perceived as separate and distinct): fuzzy, ill-defined, indistinct; see also Thesaurus:indistinct
- (not capable of being perceived): invisible, undetectable
indistinguishable (plural indistinguishables)
- Any of a set of things that cannot be distinguished.