The Collaborative International Dictionary of English v.0.48:

Unhandsome \Un*hand"some\, a.
   1. Not handsome; not beautiful; ungraceful; not comely or
      pleasing; plain; homely.
      [1913 Webster]

            Were she other than she is, she were unhandsome.
                                                  --Shak.
      [1913 Webster]

            I can not admit that there is anything unhandsome or
            irregular . . . in the globe.         --Woodward.
      [1913 Webster]

   2. Wanting noble or amiable qualities; dishonorable;
      illiberal; low; disingenuous; mean; indecorous; as,
      unhandsome conduct, treatment, or imputations. "Unhandsome
      pleasures." --J. Fletcher.
      [1913 Webster]

   3. Unhandy; clumsy; awkward; inconvenient. [Obs.]
      [1913 Webster]

            The ships were unwieldy and unhandsome. --Holland.
      [1913 Webster]

            A narrow, straight path by the water's side, very
            unhandsome for an army to pass that way, though they
            found not a man to keep the passage.  --Sir T.
                                                  North.
      [1913 Webster] -- Un*hand"some*ly, adv. --
      Un*hand"some*ness, n.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "unhandsome":
   beautiless, blemished, blotted, cacophonic, cacophonous, defaced,
   discourteous, disfigured, disrespectful, dysphemistic, dysphemized,
   homely, ill-bred, ill-mannered, impertinent, impolite, inelegant,
   marred, plain, rude, short on looks, spoiled, uglified, ugly,
   ugly as hell, ugly as sin, unaesthetic, unalluring, unattractive,
   unbeauteous, unbeautiful, uncivil, uncomely, ungracious, unlovely,
   unpleasing, unpretty, unsightly