A diminutive of Robert: cf. the obsolete Hob and Rob; also Bobbie and Robin: qq. v. From ca. 1700, though now obsolescent, it has been a colloquial term for ‘a man, a fellow’: cf. Jack and Tom, Dick and Harry, the commonness of the name giving rise to a generic sense. This may possibly be also the origin of bob, a shilling (from ca. 1810) and of the Winchester bob, a large white beer-jug; almost probably of bob, C18 slang for ‘gin’, and of the cant bob, a shoplifter’s assistant, where, however, the idea may be that of bobbing in, out, or up; and probably of the bob in wet bob and dry bob. See my Dictionary of Unconventional English, 1936. Like the other endearments (except Robin) of Robert and the original itself, it does not appear in proverbial English (Apperson).