barring (n.)youdaoicibaDictYouDict[barring 词源字典]
late 14c., "act of fastening with a bar," verbal noun from bar (v.). Meaning "exclusion" is from 1630s. As a preposition, "excepting, excluding," it is from late 15c. Schoolhouse prank of barring out the teacher was in use before 1728.[barring etymology, barring origin, 英语词源]