An approach to sexuality that treats all consensual sexual expression as healthy and free from shame or moral ranking.
The tidy version of the story credits Wilhelm Reich, the Freud-trained psychoanalyst who, in 1920s–30s Germany and Austria, split cultures into sexuell positiv (sex-affirming) and sexuell negativ. Neat, but the word we actually use today was forged later. It hardened during the feminist "sex wars" of the early 1980s, when Ellen Willis coined "pro-sex feminism" in her 1981 essay "Lust Horizons." The specific label "sex-positive" only reached its current currency in 1990s San Francisco. So if you want an honest origin: distributed, not one genius with one word.
Here's the misconception worth killing: sex-positive does not mean "always up for it," and it isn't a personality — the friend who's game for anything. More sex is not the scoreboard. It's a stance about choices, mostly other people's: your yes counts, your no counts just as much, and so do theirs. Consent is the entire engine. Take it out and the label is decoration.
Which is why abstinence and asexuality are sex-positive too. The point was never volume — it's agency. Not judging someone's kink, their number, their orientation, or their choice to sit the whole thing out. The failure mode is easy to spot once you know it: "sex-positivity" swung as a crowbar — don't be a prude, everyone's doing it — which is just the old coercion in a nicer jacket. If it pressures, it isn't positive.