This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

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adj. Not announced

adj. without warning or announcement

"Mahmoud Ahmadinejad contrasted his trip with what he called the unannounced stealth visits of other VIPs, namely U.S. officials."

unexpected   

announced    bounced    denounced    mispronounced    pounced    pronounced    renounced    trounced   

uninvited    undesired    unheralded    unscheduled    unsought    unauthorized    unasked    unlooked-for    unceremonious    unwanted