One who carries butter, eggs, and poultry to market; a packman or huckster. From cadge (to carry). Hence the frame on which hawks were carried was called “a cadge,” and the man who carried it, a “cadger.” A man of low degree.
“Every cadger thinks himself as good as an earl.” —McDonald: Malcolm, part ix. chap. xiv. p. 183.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894