IPA: /ˌʌn.kənˈsɜːrnd/
KK: /ʌnˈkənˌsɜrnd/
Not worried or anxious about something; showing a lack of concern or interest.
She remained unconcerned about the upcoming exam, believing she was well-prepared.
Unconcerned → It is formed from "un-" (meaning not) and "concerned" (from Latin "concernere", meaning to relate or to involve). The word "unconcerned" means not involved or not worried about something.
Think of 'not' ('un-') being added to 'involved' or 'worried' ('concerned') — that's why unconcerned means not worried or not involved.