barringout

from The Century Dictionary.

• noun Exclusion from a place by means of locks or bars; specifically, the act of excluding a schoolmaster from school by barricading the doors and windows: a boyish sport indulged in at Christmas in Great Britain, now nearly obsolete, and sometimes practised for mischief in parts of the United States.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of closing the doors of a schoolroom against a schoolmaster; -- a boyish mode of rebellion in schools.