आवृतं ज्ञानमेतेन ज्ञानिनो नित्यवैरिणा। कामरूपेण कौन्तेय दुष्पूरेणानलेन च ॥

āvṛitaṁ jñānam etena jñānino nitya-vairiṇā kāma-rūpeṇa kaunteya duṣhpūreṇānalena cha

Enveloped is wisdom by this constant enemy of the wise in the form of desire, which is insatiable as a flame.

In plain words: Krishna says desire is the constant enemy of wise people. It hides their wisdom, and like a fire it is never satisfied.