अप्रकाशोऽप्रवृत्तिश्च प्रमादो मोह एव च। तमस्येतानि जायन्ते विवृद्धे कुरुनन्दन ॥

aprakāśho ’pravṛittiśh cha pramādo moha eva cha tamasy etāni jāyante vivṛiddhe kuru-nandana

Darkness, stagnation and heedlessness and also delusion—these are born of the increase of Inertia, O joy of the Kurus.

In plain words: Krishna tells Arjuna that darkness of mind, feeling stuck, carelessness, and confusion are signs that dullness is growing.