Definition of "unheralded"

Union trainmen stopped traffic on six midcontinent railroads with an unheralded strike yesterday, but some railroads said they expected to resume service by early today.

1964 June 16, “Surprise Strike Stops Traffic On 6 Railroads”, in The Indianapolis Star, volume 62, number 11, Indianapolis, Ind., page 3

We all know how genius “Kamp Krusty,” “A Streetcar Named Marge,” “Homer The Heretic,” “Itchy & Scratchy: The Movie” and “Mr. Plow” are, but even the relatively unheralded episodes offer wall-to-wall laughs and some of the smartest, darkest, and weirdest gags ever Trojan-horsed into a network cartoon with a massive family audience.

2012 May 20, Nathan Rabin, “TV: Review: THE SIMPSONS (CLASSIC): “Marge Gets A Job” (season 4, episode 7; originally aired 11/05/1992)”, in The Onion AV Club‎