Synonyms of instantaneous

instantaneous

adjective

ˌin(t)-stən-ˈtā-nē-əs 

as in immediate

done or occurring without any noticeable lapse in time

the thunder following the flash of lightning was nearly instantaneous

Synonyms & Similar Words

• immediate
• instant
• rapid
• split-second
• swift
• summary
• straightaway
• quick
• speedy
• prompt
• fast
• hit-and-run

Antonyms & Near Antonyms

• slow
• prolonged
• sluggish
• protracted
• tardy
• dilatory
• deferred
• delayed

Example Sentences

Recent Examples of instantaneous

The most common type is lethal in about half of patients, and death is almost instantaneous. — Veronique Greenwood, Time, 13 July 2026

The device produces instantaneous audio that is clear, detailed, and loud, even without the aid of additional speakers. — Justin Fenner, Robb Report, 8 July 2026

The rise of Nashville Severe Weather is a modern case study in multiple areas — a shifting tornado alley, a changing climate, the prevalence of social media and the value of instantaneous, hyperlocal information that can save the day or save lives. — ABC News, 7 July 2026

With the craft's communications failing within the first two hours, the submersible imploded upon descent, resulting in their instantaneous deaths. — Dan Snierson, Entertainment Weekly, 16 June 2026