The Collaborative International Dictionary of English v.0.48:

Launder \Laun"der\ (l[add]n"d[~e]r or l[aum]n"d[~e]r), n.
   [Contracted fr. OE. lavender, F. lavandi[`e]re, LL.
   lavandena, from L. lavare to wash. See Lave.]
   1. A washerwoman. [Obs.]
      [1913 Webster]

   2. (Mining) A trough used by miners to receive the powdered
      ore from the box where it is beaten, or for carrying water
      to the stamps, or other apparatus, for comminuting, or
      sorting, the ore.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Launder \Laun"der\, v. t. [imp. & p. p. Laundered
   (l[add]n"d[~e]rd or l[aum]n"d[~e]rd); p. pr. & vb. n.
   Laundering.]
   1. To wash, as clothes; to wash, and to smooth with a
      flatiron or mangle; to wash and iron; as, to launder
      shirts.
      [1913 Webster]

   2. To lave; to wet. [Obs.] --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

launder
    v 1: cleanse with a cleaning agent, such as soap, and water;
         "Wash the towels, please!" [syn: wash, launder]
    2: convert illegally obtained funds into legal ones

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "launder":
   baptize, bath, bathe, clean, cleanse, douche, flush, flush out,
   gargle, holystone, irrigate, lather, lave, legalize, legitimate,
   legitimatize, legitimize, mop, mop up, rinse, rinse out,
   ritually immerse, scour, scrub, scrub up, shampoo, shower, sluice,
   sluice out, soap, sponge, swab, syringe, toivel, tub, wash,
   wash out, wash up