The cartoonist who lampooned Tweed is Thomas Nast, a four-letter word that is the solution to the crossword. Nast was an American caricaturist and editorial cartoonist in the 19th century who is often considered the 'Father of the American Cartoon'. He is best known for his satirical attacks on the political machine of William Marcy Tweed, which dominated New York City politics in the mid-19th century. His cartoons played a major role in the downfall of the Tweed Ring.