Green’s Dictionary of Slang

abroad adj.

1. [late 18C–mid-19C] of convicts, transported to a penal colony.

2. usu. ext. as all abroad: in boxing use, groggy, confused following a number of blows; .

3. [mid-19C] drunk.

4. [19C] general uses of sense 1: lit. or fig. confused, having lost one’s bearings; often as all abroad, extremely confused.