velox

From Proto-Indo-European *h₂weh₁-lo- (“wind”), from *h₂weh₁- (“to blow”), named after the speed of wind.^[1]

Older theories derive the word from Proto-Italic *weksloks, from Proto-Indo-European *weǵʰ- (“to bring, transport”) (whence vehō).

• (Classical Latin) IPA^(key): /ˈu̯eː.loːks/, [ˈu̯eːɫ̪oːks̠]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈve.loks/, [ˈvɛːloks]

vēlōx (genitive vēlōcis, comparative vēlōcior, superlative vēlocissimus, adverb vēlōciter); third-declension one-termination adjective

1. swift, quick, fleet, rapid, speedy

   Synonyms: rapidus, celer, properus, levis, prōmptus, facilis

   Antonyms: lentus, tardus, sērus

According to Döderlein, celer and citus mean "swift, fast, quick" in terms of quick motion (in general) with tardus as their antonym. More specifically, citus refers to a lively motion, whereas celer refers to an eager or impetuous motion.

On the other hand, vēlōx and pernīx as "quick" denote a level of athletic nimbleness in terms of bodily activity, with lentus as their antonym. More specifically, pernīx involves a level of dexterity and quickness in an eclectic range of actions (such as climbing, hurdling, jumping, vaulting, etc.); whereas vēlōx is especially used for running, swimming and flying (moving in a direction)

Thirdly, properus and festīnus as "quick" refer specifically to one's speed in terms of the shortest time to reach a destination, with sēgnis as their antonym. More specifically, festīnus intimates a certain level of impatience, whereas properus simply indicates a haste from energy simply.

Third-declension one-termination adjective.

• Pokorny, Julius (1959) Indogermanisches etymologisches Wörterbuch [Indo-European Etymological Dictionary] (in German), volume 3, Bern, München: Francke Verlag, page 1118
• “velox”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “velox”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• velox in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.