owler, n. — Green’s Dictionary of Slang

owler n.

[in an attempt to curtail smuggling the transportation of wool by night was forbidden in 1674, therefore those who still carried on the illicit trade were known as owlers, because, like the bird, they worked at night]

1. one who smuggles wool or sheep from England to France.

c.1698		B.E. Dict. Canting Crew n.p.: Owlers, those who privately in the Night carry Wool to the Sea-Coasts, near Rumney-Marsh in Kent, and some Creeks in Sussex, &c. and Ship it off for France against Law.
1725		New Canting Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1809		G. Andrewes Dict. Sl. and Cant.
1811		Lex. Balatronicum.
1835		G. Kent Modern Flash Dict.
1848		Flash Dict. in Sinks of London Laid Open.
c.1850		Duncombe New and Improved Flash Dict.
1859		Matsell Vocabulum.
1882		Dly Dispatch (Richmond, VA) 1 Nov. 3/3: ‘Owlers’ are smugglers.
1895		C. Crowe Aus. Sl. Dict. 55: Owlers, smugglers.

2. in pl. spectacles.

1841

Sheffield Indep. 7 Aug. 5/2: The officer explained that ‘norah owlers’ and ‘ridge quiz’ signified golden eye-glasses.