early 15c., "to shut out, exclude," from Fr. débarrer, from O.Fr. desbarer (12c., which, however, meant only "to unbar, unbolt," the sense turning around in Fr. as the de- was felt in a different sense), from des- (see dis-) + barrer "to bar" (see
bar (1)). Related: Debarment (1650s); debarred (1630s).