stingu-, -stingu, stinct-, -stinct

(Latin: from -stingere and -stinguere, to separate; to quench, quenching; to wipe out, to obliterate; to goad, to stick; sticking, puncturing, probing)

indistinguishable (adjective), more indistinguishable, most indistinguishable
1. Incapable of being known or perceived; exactly alike: The two identical twins were indistinguishable to their new teacher in school!
2. Not disposed to being clearly discerned or recognisable: The photo showed a new car which was quite indistinguishable from the previous one which had been produced a couple of years before, except for a few small differences.
indistinguishableness (s) (noun) (usually no plural)
indistinguishably (adverb), more indistinguishably, most indistinguishably
Pertaining to how two things cannot be differentiated from each other: The indistinguishably-perfect gem could not be perceived to have any flaws whatsoever, and the specialist could not spot any dissimilarities from the genuine one at all!
instinct (s) (noun), instincts (pl)
instinctive (adjective), more instinctive, most instinctive
instinctively (adverb), more instinctively, most instinctively