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
indistinguishableness (s) (noun) (usually no plural)
indistinguishably (adverb), more indistinguishably, most indistinguishably
instinct (s) (noun), instincts (pl)
instinctive (adjective), more instinctive, most instinctive
instinctively (adverb), more instinctively, most instinctively