Try One Of These Snappy Synonyms For “Fast,” Pronto!

Have you ever slowed down for a moment, however brief, and given a quick thought to the word fast? It might seem counterintuitive, but hear us out!

The word fast is a fascinating word. It has many different meanings, from the one you’re most familiar with (“quick, swift”), to others that you may not even know (“a chain or rope for mooring a vessel”). Beyond all the different meanings, fast also functions as many different parts of speech: it can be an adjective, adverb, noun, and even a verb. In fact, because it’s an adjective and an adverb, you don’t have to add -ly to the end to make it an adverb.

Fun fact: fastly once was the adverb form of fast, dating all the way back to Old English, but the form lost its lexical speed, as it were, a few centuries back. Fastly today is considered a nonstandard adverbial form of fast.

The word fast is an old one. It comes from the Old English fæst, meaning “firm.” By around the 1200s, the word fast extended to include a sense of “running hard,” which gave rise to the word’s meanings of “quickly” and “swiftly.” And, over the next 800 years, we continued to add and subtract meanings from the word fast.

Now that we’ve quickly given you a speedy history of the word, you might be hankering for terms about speed with a little more oomph than plain ol’ fast. Well, you’re in luck. We’ve lined up some of our favorite synonyms of fast at the starting line, and we are off to the races!

swift, swiftly

Because fast can be both an adverb and an adjective, the synonyms you choose need to match the part of speech of fast as it is used in context. Let’s take a look at an example with one of our favorite synonyms for fast, swift or swiftly.

Swift is an adjective meaning “moving or capable of moving with great speed or velocity; fleet; rapid.” While in rare instances, swift can also be an adverb, more typically the adverb form of swift is swiftly. (Adding -ly to an adjective is a common way to form an adverb.)

So, how do we know which version of swift to pick? First, we have to identify how fast is being used in the original sentence:

• Kulthoum had to work fast if he was going to leave at 5 o’clock.

Here, fast is modifying work. That makes it an adverb, so we need to use swiftly to replace it:

• Kulthoum had to work swiftly if he was going to leave at 5 o’clock.

Try it yourself! How is fast used in this sentence?

• Elodie knew she wasn’t very fast, but she still hoped that she wouldn’t come in last in the race.

Here, fast is modifying she, which is a pronoun, so it is an adjective. That means we need to use swift to replace it.

• Elodie knew she wasn’t very swift, but she still hoped that she wouldn’t come in last in the race.

Keeping this in mind will be helpful as we look at some of our other synonyms for fast. Moving swiftly on …

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brisk

To us, brisk is a word that sounds like exactly what it means. The word brisk is an adjective meaning “quick and active; lively.” It can also mean “curt or sharp.” Frequently, it’s used in the expression brisk walk, meaning a quick, purposeful walking speed.

For example:

• We went on a brisk walk around the lake for some exercise.

If you want to use brisk to replace fast as an adverb, the term you’re looking for is briskly. For example:

• Laureen stood up briskly, nearly knocking him over, and demanded to know exactly what he was talking about.

Now let’s motor on to our next word.

prompt

That’s right, we are prompting you to use prompt as a synonym for fast. We apologize for the pun, but it does a good job of showing the various meanings of prompt. Here, we are focused on prompt as an adjective meaning “done, performed, delivered, etc., at once or without delay.” (The adverbial form of prompt is promptly.)

For example:

• I wasn’t expecting a prompt reply from my student, but one arrived right away.
• Damien called his boss promptly to give him the update.

An even more intense form of prompt is …

posthaste

Posthaste is an adverb meaning “with the greatest possible speed or promptness.” As you might have guessed, the term comes from old directions to send the mail (known as the post in British English) with great speed (haste).

Now anyone can take a page out of the postman’s book and act with posthaste. For example:

• The fire department left posthaste to respond to the call about the fire.
• We went posthaste to the hospital when we heard the news.

If the mail isn’t your thing, and you’re more adventurous, you might prefer the next synonym.

Having fun yet? We have a wealth of words to use instead of fun, too. Check them out!

expeditiously

The term expeditiously is an adverb meaning “promptly and quickly.” We use expeditiously particularly to describe doing something in a short period of time in an efficient manner. (The adjective form is expeditious, and the verb is expedite.) For example:

• The judge dealt with the case expeditiously and quickly dismissed it.
• We worked expeditiously to resolve the issue.

Another synonym for fast with a bit of a nautical element is …

fleet

While fleet may make you think of a group of ships, typically for war, this term has another meaning, too: swift, rapid. The adjective fleet often sounds more formal and intensive than fast. This adjective also has an adverbial form, fleetly. (Make sure you pick the right one for the context!) For example:

• In Greek mythology, Atalanta was known for being fleet, outrunning everyone in any race.

An expression that fleet often appears in is fleet of foot, meaning “able to run very fast.” For instance:

•  You had better be fleet of foot if you don’t want to be late for the bus!

We’ve all been there. But being fleet isn’t the only kind of fast there is.

nimble

Jack be nimble, Jack be quick, Jack jump over the candlestick!

You may have encountered this nursery rhyme before. If you have, you might wonder what nimble means in this context. Nimble here means “quick and light in movement; moving with ease; agile; active; rapid.” It can also mean “quick to understand, think, devise, etc.”  This synonym for fast is especially used to describe someone who moves or acts with intelligence and deftness, like an athlete.

Nimble is an adjective, so you can use it as a synonym for fast as an adjective. The adverbial form of nimble is nimbly. For example:

• Fortunately, Lola had nimble fingers and was able to quickly undo the knot.
• Iman and Charlotte were able to nimbly evade the conductor who was checking tickets.

The word nimble can also be found in the expression nimblewit, an antonym for dumbwit. That’s right, a nimblewit is “an alert, bright, and clever person.”

Why are there so many Jacks in nursery rhymes, though? Let’s dig a little deeper into this question by reading about it here.

lickety-split

One of our favorite informal expressions used to indicate speed is lickety-split. This adverbial expression means “at great speed; rapidly.” The term is thought to be a combination of licket, a rag used to quickly wipe one’s face, and split as in split second.

As an adverbial expression, lickety-split is used to modify a verb. For example:

• We got out of there lickety-split when the cops showed up.
• Sandra jumped out of bed lickety-split and rushed to the front door.

If lickety-split is a little too informal for you, you might prefer the next expression.

in short order

In short order means “quickly, without delay.” The expression dates back to US slang in the 1800s, and like lickety-split, it is also an adverbial expression used to modify verbs:

• Don’t worry, Clarence will resolve all your issues in short order. 
• After the scandal, the mayor was removed from office, the council resigned, and the police chief quit, all in short order. 

Like we mentioned at the beginning of this slideshow, fast has many meanings besides “speedy.” Before we wrap up, we want to take a look at some synonyms you can use for other meanings of fast. The next one might truly surprise you!

true

One of the meanings of fast as an adjective is “firm in adherence; loyal; devoted.” This meaning of fast is most often found in the expression fast friends, as in a set of close friends who are very loyal to one another. Believe it or not, a synonym for fast in this sense is true.

True, like fast, has many possible meanings. One of them is “firm in allegiance; loyal; faithful; steadfast.” In this sense, a true friend is as loyal as a fast friend. For example:

•  She asked her boyfriend, “Will you stay true to me while you are away?”
• There was no doubt that Melyna had found a true ally in Thomas; he supported her no matter what.

This meaning of true can be found in the origins of the word—it comes from the Old English trēowe meaning “loyal, trusty, honest.”