tanner (n.1)

"one who tans leather," Old English tannere, agent noun from tannian (see tan (v.)).

"sixpence," slang word first recorded 1811, of unknown origin. J.C. Hotten, lexicographer of Victorian slang, thinks it may be from tanner and skin, rhyming slang for "thin," presumably in reference to the smallness of the coin. Not to be confused with tenner, slang for "ten-pound note," which dates from 1861.