What is "bum steer"

n. (context idiomatic English) bad advice or information, regardless of intention.

To give a bum steer is a predominantly Australian and New Zealand idiom that means to provide information, intentionally or unintentionally, that is incorrect, was unhelpful, or caused one to be led astray. The phrase is not generally regarded as pejorative. The idiom, as used in Australia and New Zealand, reached the United States in the 1920s probably after exposure to Australian troops on the Western Front during World War I, and is recorded in the UK since 1944.

Its origin is possibly from 19th century American maritime humour and the difficulty of trying to steer a vessel in reverse. A ship's stern is flat and lacks the pointed structure of a bow, and a ship is therefore difficult to maneuver in reverse when using the rudder, also found on the stern. The reverse maneuvering was accomplished therefore through shouted instructions from the wharf to the wheelhouse, via intermediary deckhands. Such communication was prone to misunderstanding owing to the wide variety of nationalities employed on United States merchant vessels during the 19th century.

Originally, the "steer" in the idiom is not related to the male cattle also called steers.