unannounced
UK: ˌʌnəˈnaʊnst | US: ˌʌnəˈnaʊnst
adj. not announced or declared beforehand
adj. happening without prior notice
The word "unannounced" combines the prefix "un-" (Old English "un-," meaning "not") with "announce" (from Latin "annuntiare," meaning "to declare," via Old French "annoncer") and the suffix "-ed" (indicating past participle form). The prefix negates the action of announcing, creating a term for something that occurs without prior declaration. This structure reflects a straightforward logical progression: "not declared in advance."
The CEO made an unannounced visit to the factory.
Her arrival was completely unannounced, surprising everyone.
The policy change came unannounced, causing confusion.
He entered the meeting unannounced and took a seat.
The band played an unannounced gig at a small club.