carnavaliser

A rare, academic term from literary and cultural criticism (rooted in the concept of the "carnivalesque" popularized by Bakhtin) meaning to give something a mocking, hierarchy-inverting, carnival-like quality — turning normal order upside down the way an actual carnival temporarily does. Almost exclusively a literary/academic-register word.

• Le roman carnavalise les institutions religieuses de l'époque. — The novel treats the religious institutions of the era in a mocking, carnivalesque way.
• Cette satire carnavalise le pouvoir politique en le tournant en ridicule. — This satire gives political power a carnivalesque treatment, turning it into ridicule.
• Les fêtes médiévales carnavalisaient temporairement l'ordre social. — Medieval festivals temporarily turned the social order upside down, carnival-style.

This is specialized literary-criticism vocabulary, not everyday French — don't reach for it to describe an actual carnival event (fêter or célébrer le carnaval is the plain way to say that); carnavaliser specifically means treating something with a mocking, upside-down carnival spirit.