Synonyms of at once

at once

phrase

1

as in concurrently

at one and the same time

I have three papers due all at once.

Synonyms & Similar Words

• concurrently
• simultaneously
• together
• coincidently
• in unison
• immediately
• contemporaneously
• coincidentally
• near
• close
• narrowly

Antonyms & Near Antonyms

• separately
• apart
• independently
• individually
• singly
• successively
• consecutively

2

as in now

without delay

Call me at once when you get this message.

Synonyms & Similar Words

• now
• immediately
• directly
• promptly
• instantly
• right
• right now
• soon
• shortly
• right off
• suddenly
• right away
• presently
• in no time
• on the spot
• away
• straight off
• quickly
• on the double
• forthwith
• headlong
• on a dime
• instantaneously
• straightway
• straightaway
• PDQ
• incontinently
• off the bat
• momentarily
• abruptly
• plumb
• pronto
• rapidly
• quick
• bang
• instanter
• freely
• swiftly
• readily
• swift
• hastily
• fast
• unexpectedly
• speedily
• briskly
• apace
• anon
• exactly
• recklessly
• impetuously
• fleetly
• rashly
• impulsively
• snappily
• presto
• full-tilt
• punctually
• posthaste
• opportunely
• seasonably

Antonyms & Near Antonyms

• slowly
• late
• tardily

Example Sentences

Recent Examples of at once

This process is repeated contaminant by contaminant, though a single glass of tap water may contain dozens of trace contaminants at once. — Christine Kirchhoff, The Conversation, 30 July 2026

Duke delivers a crushing sequence of blows to claim the championship belt, and both brothers’ dreams come true at once. — Ben Travers, IndieWire, 30 July 2026

As if one night all the lights in all the buildings would be turned off at once, and the cars and the street lamps and the screens, and even the stars would be dark overhead, and there is the moon. — Gabriel Winslow-Yost, New Yorker, 30 July 2026

This spacing reduced the likelihood that Ukraine could identify and strike the entire formation at once. — Vikram Mittal, Forbes.com, 29 July 2026