Hogwash is a strong, informal way to say “that is nonsense” or “that is not true.” If someone tells a story that sounds fake, you can say “That’s hogwash.” It is not a school-essay word and not a polite word for a speech; it belongs in talk, in punchy writing, in arguments. The feeling is “this is rubbish” — empty or untrue talk. Long ago the same word meant the dirty leftover food and water that people gave to pigs; that farm meaning has almost died, and almost everyone who says hogwash now means stupid or untrue talk. It sounds a little old-fashioned and colourful, not like this year’s teen slang, but people still use it when they want to push a claim away with one word.