الْجَامِحُ فِي جَهَالَاتِهِ، الْجَانِحُ إِلَى خُزَعْبَلَاتِهِ
Unrestrained in his ignorance, inclined toward his absurd fancies!
Al-jāmiḥ evokes a creature running beyond control; al-jāniḥ means leaning or turning toward something. Khuzaʿbalāt refers to foolish or baseless notions.
Jāmiḥ / jāniḥ sound close but are not synonyms: one suggests unrestrained motion, the other a chosen direction. The similarity in sound makes the contrast memorable.