out of left field

The phrase "out of left field" is an idiom that means unexpected or surprising. It is often used to describe something that is unforeseen, unconventional, or comes from an unexpected or unrelated source. The origins of the phrase can be traced back to baseball, where the left field is typically the farthest from the batter and where unexpected plays or hits often occur. Thus, something "out of left field" is unexpected in a similar manner.