give someone a bum steer

Example: “The guy at the gas station gave us a bum steer, and we ended up on a dirt road.”

Origin: American slang from the turn of the 20th century, first documented in an 1898 Denver newspaper, and its exact source is genuinely contested. One theory looks to American cowboy culture, where "steer" (to direct cattle, or the cattle themselves) combines with "bum" (worthless, faulty) for advice that leads someone in the wrong direction the way a bad drover might misdirect a herd — though this connection is unconfirmed. A second, less-cited theory points to maritime slang, built on the genuine difficulty 19th-century sailors had steering a ship in reverse, its stern lacking the bow's more predictable lines and prone to unexpected, miscalculated turns. The phrase spread from the United States to Australia and New Zealand, then apparently traveled back across the Pacific via Australian troops in the First World War before becoming established in British English by the 1940s.