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Definitions

at once

ADJECTIVE
immediate
Synonyms
STRONGEST
actual prompt urgent
WEAK
at present time at this moment critical current existing extant first hair-trigger instant live next now on hand paramount present pressing up-to-date
Antonyms
WEAK
away distant eventually far later never
ADVERB
directly
Synonyms
STRONGEST
immediately instantaneously instantly promptly quickly shortly
STRONG
forthwith straightaway
WEAK
anon contiguously dead due first off in a second instanter presently pronto right away speedily straight off
Antonyms
STRONGEST
eventually later
WEAK
indirectly
ADVERB
early
Synonyms
STRONGEST
directly first promptly recently right away soon timely
STRONG
betimes
WEAK
freshly in a jiffy in an instant in no time instantaneously instantly newly presto primitively seasonably straightaway summarily thereon thereupon without delay
Antonyms
STRONGEST
later
WEAK
late
ADVERB
ensemble
Synonyms
STRONG
altogether
WEAK
all at once as a body as a group as a whole as one en masse in concert
ADVERB
forthwith
Synonyms
STRONGEST
abruptly right away
STRONG
directly instantly now straightaway
WEAK
away quickly right now suddenly tout de suite without delay
Antonyms
STRONG
later
ADVERB
hand over fist
Synonyms
WEAK
ASAP amain apace immediately increasingly instantly speedily
ADVERB
in a moment
Synonyms
WEAK
in a trice in a wink in an instance momentarily momently right away very soon
ADVERB
instantaneously
Synonyms
STRONGEST
right away spontaneously
WEAK
directly immediately pronto quickly
ADVERB
instantly
Synonyms
STRONGEST
directly immediately instantaneously right away
STRONG
forthwith now
WEAK
PDQ away double-time first off in a flash instanter on a dime pronto right spontaneously straight away there and then this minute tout de suite without delay
Antonyms
STRONG
later
WEAK
eventually
ADVERB
now
Synonyms
STRONGEST
today
STRONG
directly forthwith immediately instantly nowadays straightaway
WEAK
PDQ any more at the moment at this moment at this time away first off here and now in a minute in a moment in nothing flat instanter just now like now momentarily on the double promptly pronto right away right now soon these days this day
Antonyms
STRONG
eventually later
WEAK
future past
ADVERB
now
Synonyms
STRONG
forthwith instantly straightaway
Antonyms
STRONG
later
WEAK
future past
ADVERB
posthaste
Synonyms
WEAK
breakneck directly double-quick expeditious flat-out fleet fleetly full tilt hastily hasty headlong lickety-split pell-mell promptly pronto quick quickly rapid rapidly speedily speedy straightaway swift swiftly
ADVERB
promptly
Synonyms
STRONGEST
directly expeditiously hastily instantly quickly rapidly speedily swiftly
STRONG
pronto
WEAK
PDQ fast flat-out fleetly in nothing flat lickety-split like a shot now on the dot on the double on time posthaste punctually right away sharp straightaway unhesitatingly
Antonyms
STRONGEST
slowly
WEAK
late negligently
ADVERB
readily
Synonyms
STRONGEST
cheerfully eagerly easily freely gladly immediately promptly willingly
WEAK
at the drop of a hat facilely hands down in a jiffy in no time lightly no sweat nothing to it piece of cake quick as a wink right away slick as whistle smoothly speedily straight away swimmingly unhesitatingly well without delay without demur without difficulty without hesitation
Antonyms
STRONGEST
difficultly grudgingly unwillingly
ADVERB
right
Synonyms
STRONGEST
away straight
STRONG
direct due now
WEAK
first off forthwith immediately instanter instantly promptly quickly right away straight away straightly undeviatingly
Antonyms
WEAK
inaccurately inappropriately incorrectly indirectly unfairly unjustly unsuitably wrongly
ADVERB
right off
Synonyms
WEAK
anon contiguously dead due first off forthwith immediately in a second instant instantaneously instanter instantly now presently promptly pronto quickly right away shortly speedily straight off straightaway
ADVERB
right off the bat
Synonyms
WEAK
immediately instantly on the dot
ADVERB
straight
Synonyms
STRONGEST
away dead right away
STRONG
direct due now right straightaway
WEAK
as the crow flies exactly first off forthwith in direct line instanter instantly lineally point-blank straightforwardly straightly undeviatingly
Antonyms
STRONG
indirectly
WEAK
later
ADVERB
straightaway
Synonyms
STRONG
dead due forthwith immediately instant instantly now right straight
WEAK
anon contiguously direct first off in a second instantaneously instanter presently promptly pronto quickly right away right off shortly speedily straight off
Antonyms
STRONG
eventually indirectly later
ADVERB
straight off
Synonyms
WEAK
anon contiguously dead due first off forthwith immediately in a second instant instantaneously instanter instantly now presently promptly pronto quickly right away right off shortly speedily straightaway
ADVERB
tout de suite
Synonyms
WEAK
in a wink in an instant now pronto right away without delay

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

This structure helps solve several problems at once.

From Science Daily • Apr. 19, 2026

Driven by Gen Z and millennials, 25% of borrowers hold three or more BNPLs at once, with 29% turning to those for groceries and 20% for delivery or takeout.

From MarketWatch • Apr. 16, 2026

“But rates dipped just before the war, and everyone seemed to come out all at once to bid for homes that had been on the market for over 20 days.”

From Los Angeles Times • Apr. 15, 2026

“Don’t expect it all to be started at once, this will build. Blockades take time to have an impact.”

From The Wall Street Journal • Apr. 14, 2026

It was close, yet it came from all directions at once.

From "Black Star, Bright Dawn" by Scott O'Dell