(The). The “wrong” or worst side; as, the “seamy side of Australia,” “the seamy side of life.” Thus, in velvet, in Brussels carpets, in tapestry, etc., the “wrong” side shows the seams or threads of the pattern exhibited on the right side.
“You see the seamy side of human nature in its most seamy attire.” —Review of R. Buchanan's play Alone in London, November, 1885.
“My present purpose is to call attention to the seamy side of the Australian colonies. There is, as we know, such a thing as cotton-backed satin; but the colonists take care to show us only the face of the goods.” —Nineteenth Century, April, 1891, p. 524.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894