If this word looks to you like it should be a famous vegetable, maybe it’s time to bring you up to speed on it. This is not food fast or slow, nor a star who’s fallen off the b-list; it’s more a characteristic of a tercel, if not always of a Toyota Tercel.
Celerity is what you have after acceleration (ac ‘to’ plus celer plus ation) and before deceleration. If you want to get somewhere in a trice – can we say get there tricely? – you need celerity or ye will be derelict. Let me add some clarity: celerity is speed, from Latin celer ‘swift’. It is a business-class or first-class word for speed. And just as business and first will get you to your destination at the same time as economy, but with more expense and ostentation, so celerity will serve the same sense as speed, but with a Rolex chronograph on its wrist.
There are other synonyms for speed, of course; Merriam-Webster’s thesaurus includes fastness, fleetness, haste, hurry, quickness, rapidity, rapidness, speediness, swiftness, and velocity. But they don’t all have exactly the same tinges and tastes. Some imply time pressure, some have a sense of carelessness; others are dryer or more positively toned. Several have that –ness that drags like a trailer. One thing nearly all of them do have, though, is a fricative at the start: /s/, /f/, /h/ (only sort of a fricative in English, admittedly), and the one voiced one the engine-rev /v/. Two others have the liquid /r/. Only one starts with a stop: quickness.
Of them all, celerity is truly the most rare and expensive – the only one that the average speaker might not even know. It is a shining silver streak of a word, soft and liquid with one lightly crisp tap as it passes. It may have a more lyric quality, even. It is ethereal and yet somehow slightly lesser in impact.
I do not think that this watch is truly a businessman in business class drinking his transatlantic Caesar with celery. No, it is a wisp of a lady in a diaphanous dress wearing not a watch at all but simply a silver bracelet, sitting in first class sipping Perrier-Jouet and talking to no one as she sees the Pacific slip quickly away below. Who is she? A starlet? A food guru? A simple skater? No one knows for sure, except for that bespectacled nerd sitting next to her reading impenetrable theory for relaxation. He is flying as fast as she is, and he will arrive with her at the same hotel room. And he knows what celerity is. Not haste. Not hurry. No pressure. Simply being everywhere before the slower ones.