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

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v. Present participle of vociferate.

"Then a drunken major shouted a challenge from the doorway of a cantina and began vociferating orders, and as they left the plaza behind they could hear rising the familiar mob-cry "Kill the Gringos!""

whisper   

vociferated    vociferates    vociferating   

verbalise    give tongue to    express    verbalize    utter   

shout   

vociferated    vociferating   

exclaim    bawl    clamor    shout    bellow