IPA: //ʌnprɪˈpɛrd//
KK: /ʌnprɪˈpɜrd/
Not ready or equipped for a situation or event because no preparations have been made.
She felt unprepared for the exam because she hadn't studied.
Unprepared → It is formed from "un-" (meaning not) and "prepared" (from Latin "parare", meaning to make ready). The word "unprepared" means not made ready or not equipped for a situation.
Think of 'not' ('un-') being added to 'made ready' ('prepared') — that's why unprepared means not ready.