atrophier

To atrophy — a muscle, organ, or skill wasting away from disuse (le muscle s'atrophie sans exercice). It extends naturally to figurative use for skills or institutions weakening from neglect (son sens critique s'est atrophié).

• Le muscle s'atrophie si on ne l'utilise pas. — The muscle atrophies if you don't use it.
• Son imagination semble s'être atrophiée. — His imagination seems to have withered.
• L'immobilité prolongée atrophie les jambes. — Prolonged immobility causes the legs to atrophy.

Almost always used reflexively (s'atrophier) since the subject shrinks or wastes on its own from disuse — learners sometimes force a transitive construction that sounds unnatural outside medical contexts.