swift, quick, fleet, rapid, speedy
From Proto-Indo-European *h₂weh₁-lo- (“wind”), from *h₂weh₁- (“to blow”), named after the speed of wind. Older theories derive the word from Proto-Italic *weksloks, from Proto-Indo-European *weǵʰ- (“to bring, transport”) (whence vehō).
Practice speaking and memorizing "velox" and many other words and sentences in Latin.