Definition: directly opposite or opposed
The word was found in the newspaper on Monday November 3, 2014. The word is located in the middle of the article http://www.nytimes.com/2014/10/28/nyregion/flickering-lights-strange-music-and-a-ghost-at-a-brooklyn-restaurant-maybe.html. The sentence began “Antithetical to the neighborhood today, the working classes pushed out the wealthy, knocking down mansions to build tenements, according to John B. Manbeck, a former Brooklyn borough historian.”
At first I didn’t understand the word, however I looked up the word and put together the with the sentence. The word is being used to describe the people in the neighborhood, they oppose the idea.