C20: from baseball term left field, the area of the outfield to the batter's left, regarded as the scene of little action
left field for learners of EnglishPowered by COBUILD
1. singular noun
If you say that someone or something has come out ofleft field or is out inleft field, you mean that they are untypical, unusual, or strange in some way. ⇒ The question came out of left field, but Mary Ann wasn't really surprised. ⇒ He is, like most theorists, out there in left field, ignoring the experimental evidence.
2. graded adjective & adjective [usu ADJ n]
Left-field means slightlyodd or unusual. [mainly British, informal] ⇒ ...a left-field cabaret act. ⇒ Her parents were creative and left-field and wanted Polly to become a singer or a truck driver.