BG 6.34
चञ्चलं हि मनः कृष्ण प्रमाथि बलवद्दृढम्। तस्याहं निग्रहं मन्ये वायोरिव सुदुष्करम्
chañchalaṁ hi manaḥ kṛiṣhṇa pramāthi balavad dṛiḍham tasyāhaṁ nigrahaṁ manye vāyor iva su-duṣhkaram
My Lord! Verily, the mind is fickle and turbulent, obstinate, and strong; indeed, it is extremely difficult to control, like the wind.
Translated by Shri Purohit Swami
The mind is indeed restless, turbulent, strong, and unyielding, O Krishna; I consider it as difficult to control as controlling the wind.
Translated by Swami Sivananda
Word meanings (from the gita/gita dataset)
chañchalam—restless; hi—certainly; manaḥ—mind; kṛiṣhṇa—Shree Krishna; pramāthi—turbulent; bala-vat—strong; dṛiḍham—obstinate; tasya—its; aham—I; nigraham—control; manye—think; vāyoḥ—of the wind; iva—like; su-duṣhkaram—difficult to perform