IPA: //ʌnˈprɛsɪˌdɛntɪd//
KK: /ʌnˈprɛsɪˌdɛntɪd/
Something that has never happened before or has no previous example.
The pandemic caused an unprecedented change in how we work and live.
Comparative: more unprecedented
Superlative: most unprecedented
Unprecedented → It is formed from "un-" (meaning not) and "precedent" (from Latin "praecedens", meaning going before). The word "unprecedented" means not having a previous example or instance, indicating something that has never happened before.
Think of something that is 'not' ('un-') 'going before' ('precedent') — that's why unprecedented means something that has never happened before.