stinct

Everything in this family starts with one physical act: jabbing something with a sharp point. The Latin verb stinguere meant 'to prick' or 'to goad,' and a goad is exactly that — a pointed stick a herdsman jabs into an ox to make it move. Hold that picture, because it explains a surprisingly scattered set of English words.

The first branch is about telling things apart. dis- means 'apart,' and distinguere literally meant to 'prick apart' — to mark separate things with separate pricks, like notching tally sticks so you can tell one from another. From that come distinguish (to tell apart), distinct (clearly marked off, separate), distinction (the difference itself, or the mark of honor), and distinctive (carrying a mark that sets something apart). Add in- ('not') and you get indistinct — not marked off clearly, blurry — and indistinguishable — impossible to prick apart.

The second branch turns the prick inward. in- ('in, inside') + stinguere gives instinct: a prick from inside, an impulse that goads you to act before you have time to think. A bird does not decide to build a nest; an inner goad pushes it. From there: instinctive, instinctively.

The third branch keeps the goad but aims it at other people, through the variants stim- and stig-. stimulus was the Latin word for the herdsman's actual pointed stick; to stimulate is to poke something into motion — an economy, a nerve, a curiosity. A stimulant is a substance that does the poking. And instigate (in- + the stig- form) is to goad someone into action, usually trouble: the instigator is the one holding the stick.

A fourth branch comes from Greek rather than the goad. stigma was the mark left by a brand or tattoo — the prick that marked a slave or a criminal. So a stigma is a mark of shame, and to stigmatize is to brand someone with disgrace.

The last branch looks unrelated but is built on the same verb. ex- ('out') + stinguere meant to 'prick out' — and the way you prick out a flame is to put it out. So extinguish means to quench a fire, an extinguisher is the tool for it, and extinct describes a fire (or a whole species) that has gone out for good; extinction is the going-out.

Quick read on the spellings: -t- forms (distinct, instinct, extinct) come from the participle stem; the -gu- forms (distinguish, extinguish) keep a softened spelling; stim- and stig- preserve the cattle-goad and the brand-mark. And sting/stingy/stinginess are English cousins, not Latin imports — same ancient 'prick' root, different doorway into the language.