IPA: /ʌnˈprɛsɪdɛntɪdli/
KK: /ʌnˈprɛsɪdɛntɪdli/
In a way that has never happened before; without any previous example.
The team achieved unprecedentedly high scores in the competition.
Unprecedentedly → It is formed from "un-" (meaning not), "precedent" (from Latin "praecedens", meaning going before), and "-ly" (meaning in a manner). The word "unprecedentedly" means in a manner that is not based on any previous example or occurrence.
Think of something that is 'not' ('un-') based on anything that has 'gone before' ('precedent') — that's why unprecedentedly means in a way that has never happened before.