compasser

Compasser is a rare, old-fashioned verb meaning to measure precisely (with a compass, historically) or, figuratively, to regulate one's manner in a stiff, overly formal way. It survives almost exclusively today as the adjective compassé (stiff, starchy), rather than as an active verb.

• Autrefois, l'architecte compassait chaque mesure avec soin. — In the past, the architect precisely measured every dimension with a compass.
• Il compasse ses gestes comme s'il craignait de mal faire. — He measures his gestures precisely, as if afraid of getting it wrong.
• On dit surtout aujourd'hui qu'une personne a un air compassé, plutôt que d'utiliser le verbe lui-même. — Today people mostly say someone has a compassé (stiff) manner, rather than using the verb itself.

This verb is essentially obsolete as an active verb — the one thing worth knowing is that its past participle, compassé, lives on as a common adjective meaning stiff or overly formal, so don't be surprised the adjective feels far more familiar than the verb.