Without prior warning; unexpected or unannounced(adjective)
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Use "unheralded" in a sentence
"* "All politics is local": The old Tip O'Neill adage took a beating for the third straight House election cycle, as a national wave swept out good campaigners and swept in unheralded and underfunded candidates."
"But while everyone around her was jockeying for the best view of Ingmar Guandique, the man who would later be convicted of Levy's murder, Amico waited patiently for the clerk to call the unheralded case of Vernon McRae, a 22-year-old Southeast man charged with fatally wounding Michael Washington, 63, during an argument in October."
"Perhaps in an area kind of unheralded where we've done the most good in the last five years is in protecting and making more portable pension plans."