woadster

From Middle English wodester, equivalent to woad (“to dye with woad”) +‎ -ster.

woadster (plural woadsters)

1. (rare, historical) One who dyes with woad
   • 1979, Corliss Lamont, ‎John Mansfield, Letters to Florence Lamont, page 170:

     If you come across a man called Wadster you can be fairly sure that his ancestors were woadsters and dealt in blue dye.

   • 2014, original letter: 1877, William Morris, ‎Norman Kelvin, The Collected Letters of William Morris, volume 1, page 395:

     As to the blue-dyeing, I think it would be certainly a very good think to get a woadster over; though you know the old books all say that the woad vat is not good for silk: I don't know why, unless perhaps that the lime is bad for it: still he might help us in setting a potash vat (Cuve-d-Inde).