Across the multilingual area of the Vaupés River Basin in north-west Amazonia, women are considered a dangerous ‘other’. In accordance with the local marriage practices, men marry women from language groups different to their own. Women are denied access to important rituals, such as the Yurupary rite, and are not supposed to hear any words associated with this tradition. The paper addresses a special linguistic practice of a women-directed taboo, so far documented just for the Tariana (the only Arawak-speaking groups in the Vaupés River Basin area). All the paraphernalia associated with the Yurupary ritual and a number of place names which contain the name of the Yurupary flute are a taboo to women, and so their original names cannot be pronounced in the presence of women. If a woman is present, a tabooed form has to be used instead. The tradition is on the way out, since the Tariana language and culture are severely endangered. The ‘taboo against women’ in Tariana is compared with other systems of gender-based taboos across the world. How did the erstwhile secret knowledge become public? And how can one get access to ‘forbidden’ knowledge in the Amazonian context? These issues are addressed at the end of the paper.