ETYMOLOGY
? from cob (a big man, a great man, a leading man) + castle
EXAMPLE
“…’Twixt the wood and the castle they see at high water
The storm, the place makes it a dangerous matter;
And besides, upon such a steep rock it is founded,
As would break a man’s neck, should he’scape being drowned:
Perhaps though in time one may make them to yield,
But ’tis prettiest Cob-castle e’er I beheld…”
From: Poems on Several Occasions written by Charles Cotton, 1689
A Voyage to Ireland in Burlesque
Lexicophilia 