Instant
Instant adjective - Done or occurring without any noticeable lapse in time.
Once and instant are semantically related In some cases you can use "Once" instead a conjunction "Instant".
Once
Once adjective - Having been such at some previous time.
Instant and once are semantically related in as soon as topic. Sometimes you can use "Instant" instead a conjunction "Once".
Both words in one sentence
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Instant Seduction: Occurs not once, but twice, the first time involving Telly talking a young virgin into having sex in literally a minute and a half.
Source: Film / Kids -
The last of these, Foxy the Pirate, instead chooses to skip the foreplay creepiness entirely once triggered and flat-out bums rushes you for an instant game-over if he makes it.
Source: Leeroy Jenkins -
Once hunger was introduced, food no longer were instant heals (Potions of Healing covered that), but instead, food takes about 3 seconds to fully consume and they restore hunger points instead.
Source: Scrappy Mechanic
Cite this Source
Once and Instant. (2016). Retrieved 2026, July 29, from https://thesaurus.plus/related/instant/once
Instant & Once. N.p., 2016. Web. 29 Jul. 2026. <https://thesaurus.plus/related/instant/once>.
Once or Instant. 2016. Accessed July 29, 2026. https://thesaurus.plus/related/instant/once.
Google Ngram Viewer shows how "instant" and "once" have occurred on timeline