merchant of eel-skins, n. — Green’s Dictionary of Slang

merchant of eel-skins n.

[? his slipperiness, the unlikeliness of their supposed commodity]

one who only poses as a merchant.

1546		J. Heywood Proverbs II Ch. v: We shall see him prove a merchant of eels-skins – / A merchant without either money or ware.
1658		J. Howell Paroimiographia Proverbs 15: A Merchant of Eel-skins.
1662		G. Torriano The second alphabet consisting of proverbial phrases 68: Esser Mercantuccio di fusaglia, i.e. Mercantuccio di poco conto, to be a bean Merchant, viz. a pityfull Pedlar, a Merchant of Eel-skins.