expression, ichidan verb
chase away gloom; dispel melancholy
Rare, literary phrase meaning to actively dispel one's depressed mood or gloomy thoughts. The verb 散じる here is an older or more formal equivalent of 散らす, used in a figurative sense.
彼は散歩に出て、鬱を散じようとした。
He went for a walk to try to chase away his gloom.
The phrase combines 鬱 (gloom, depression) with the verb 散じる, an older or literary form of 散らす (to scatter, disperse). The exact historical origin is uncertain, but it follows a pattern of figurative expressions for dispelling negative emotions.