काममाश्रित्य दुष्पूरं दम्भमानमदान्विताः। मोहाद्गृहीत्वासद्ग्राहान्प्रवर्तन्तेऽशुचिव्रताः ॥

kāmam āśhritya duṣhpūraṁ dambha-māna-madānvitāḥ mohād gṛihītvāsad-grāhān pravartante ’śhuchi-vratāḥ

Surrendering themselves to insatiable desires, possessed with vanity, conceit and arrogance, holding evil ideas through delusion, they engage in action with impure resolves.

In plain words: Krishna says people with a demonic nature give in to desires that are never satisfied. They are full of vanity and arrogance, believe wrong ideas because they are confused, and act with selfish, unclean goals.