IPA: /ˌʌndɪˈklɛrd/
KK: /ʌndɪˈklɛrd/
Not officially stated or announced; something that has not been declared or made known.
She is an undeclared major, meaning she hasn't chosen a specific field of study yet.
Undeclared → It is formed from "un-" (meaning not) and "declare" (from Latin "declarare", meaning to make clear or announce). The word "undeclared" means not announced or made clear.
Think of 'not' ('un-') making something 'clear' or 'announced' ('declare') — that's why undeclared means something that hasn't been made clear.