The Collaborative International Dictionary of English v.0.48:

Unsightly \Unsightly\
   See sightly.

WordNet (r) 3.0 (2006):

unsightly
    adj 1: unpleasant to look at; "unsightly billboards"

Moby Thesaurus II by Grady Ward, 1.0:

78 Moby Thesaurus words for "unsightly":
   beat-up, beautiless, bedraggled, blemished, blotted, blowzy,
   cacophonic, cacophonous, careless, chintzy, defaced, dilapidated,
   disfigured, drab, drabbletailed, draggled, draggletailed, dull,
   dysphemistic, dysphemized, frowzy, frumpish, frumpy, grubby,
   hideous, homely, horrible, ill-favored, ill-looking, ill-shaped,
   in rags, inelegant, informal, lackluster, loose, lumpen, marred,
   messy, mussy, negligent, plain, poky, ragged, raggedy, ruinous,
   scraggly, seedy, shabby, shoddy, short on looks, slack, slatternly,
   slipshod, sloppy, slovenly, sluttish, sordid, spoiled, squalid,
   tacky, tattered, uglified, ugly, ugly as hell, ugly as sin,
   unaesthetic, unattractive, unbeautiful, uncomely, unhandsome,
   unkempt, unlovely, unneat, unpleasing, unprepossessing, unpretty,
   unshapely, untidy