Speed In French, French words for speed include vitesse, rapidité, allure, promptitude, lancer, aller à toute vitesse, aller à toute allure and progrès. to be. Simply enter the word you French speed limits, unlike the UK are variable. Definition of speed verb in Oxford Advanced Learner's Dictionary. Synonym Discussion of Speed. Translate "speed" from English to French, vitesse, pas, rapidité, speed limit, high speed, speed up, . Learn the translation for ‘speed’ in LEO’s English ⇔ French dictionary. See word usage in contexts, conjugation and declension. Over 100,000 French translations of English words and phrases. Prosperity; success.