The Collaborative International Dictionary of English v.0.48:

Dowdy \Dow"dy\, a. [Compar. Dowdier; superl. Dowdiest.]
   [Scot. dawdie slovenly, daw, da sluggard, drab, Prov. E. dowd
   flat, dead.]
   Showing a vulgar taste in dress; awkward and slovenly in
   dress; vulgar-looking. -- Dow"di*ly, adv. -- Dow"di*ness,
   n.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dowdy \Dow"dy\, n.; pl. Dowdies.
   An awkward, vulgarly dressed, inelegant woman. --Shak.
   Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dowdy
    adj 1: lacking in smartness or taste; "a dowdy grey outfit"; "a
           clean and sunny but completely dowdy room"
    2: primly out of date; "nothing so frumpish as last year's
       gambling game" [syn: dowdy, frumpy, frumpish]
    n 1: British marshal of the RAF who commanded the British air
         defense forces that defeated the Luftwaffe during the
         Battle of Britain (1882-1970) [syn: Dowding, Hugh
         Dowding, Baron Hugh Caswall Tremenheere Dowding,
         Dowdy]
    2: deep-dish apple dessert covered with a rich crust [syn:
       dowdy, pandowdy]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "dowdy":
   archaic, blowsy, bygone, dated, demode, down-at-heel,
   down-at-the-heels, drab, draggletailed, dull, frayed, frazzled,
   frowsy, frowzy, frumpish, frumpy, full of holes, holey, in rags,
   in shreds, in tatters, messy, old hat, old-fashioned, out-of-date,
   outdated, outmoded, passe, patchy, ragged, raggedy, ratty, scruffy,
   seedy, shabby, shoddy, slattern, sloppy, slovenly, slut, sordid,
   stodgy, tacky, tattered, tatty, torn, traipse, unbecoming,
   unfashionable, unkempt, unseemly, vintage