(n.) someone who is up to no good
If you’re a busy-gap rogue, then you’re up to no good. That’s a term with roots in sixteenth and seventeenth century English slang (if not a little earlier), and was particularly in use in the northern half of England. Why the north in particular? Well, that’s where the eponymous Busy Gap itself is located.
Busy Gap (whose name is perhaps a corruption of bushy) is one of the oldest named locations along the length of Hadrian’s Wall, the grand Roman construction that almost completely connects the east and west coasts of northern England. The wall was originally constructed to product Roman-era England from invading Scots, but long after the Empire had collapsed and Roman influence had dissipated in England, the borderlands remained a dangerous place.
From the thirteenth century onwards, bands of brigands and thieves from both sides of the border operated across northern England and southern Scotland. The Border Reivers, as they were known, attacked farms and settlements with little regard to their nationality—indeed the Reivers themselves were a mixture of Englishmen and Scots.
No matter their origin, however, Busy Gap—providing a natural break in the surrounding landscape—apparently proved one of their favourite haunts.
Busy Gap is a wide break in the ridge of basalt, about a mile from Sewingshields. This was the pass most frequently chosen by the freebooters of the Middle Ages when on their marauding expeditions to the rich valley of the Tyne, and hence it acquired an evil reputation.
Richard Heslop, Northumberland Words (1892)
Busy Gap was also for many centuries the site of encampments of seasonal workers who would arrive in the border country in the spring and summer to find work among the local farms and crofts. It’s possible that the behaviour or reputation of these itinerant workers might have helped inspire this term too—or perhaps their camps, which would have been little more than temporary shelters or shiels, proved a prime target for the thieves and Reivers already operating in the area.
Whatever the inspiration, this point in the wall somehow became immortalized in this expression, which apparently remained current in northern English into the nineteenth century.