adjective (a)

• having no beneficial use or incapable of functioning usefully(adj.all)

  Example:
  A kitchen full of useless gadgets.
  She is useless in an emergency.
  

  Antonym:
  useful, utile
  

  source: wordnet30
• Having, or being of, no use; unserviceable; producing no good end; answering no valuable purpose; not advancing the end proposed; unprofitable; ineffectual; as, a useless garment; useless pity.(adjective)

  source: webster1913