فَتَرَى خَلْفَهَا مِنَ الرَّجْعِ وَالسَّوْقِ ۞ مَنِينًا كَأَنَّهُ إِهْبَاءُ
Translation: Behind her movement and driving pace, fine dust is visible, as though dispersed dust were spreading through the air.
Al-rajʿ denotes turning or returning, al-sawq forward urging, and manīnan fine dust. Ihbāʾ evokes airborne dust.
Rather than simply calling the animal fast, the poet describes a visible consequence of its motion: the dust it leaves behind. The image makes speed concrete.