Compounds of 無用

• 無用
  (adj-na,n,adj-no) useless
  futility
  needlessness
  unnecessariness
  (P)
• 無用心
  (adj-na,n) insecurity
  carelessness
• 心配無用
  (exp) Don't worry about it
  There is nothing to fear
  There is no need for anxiety
  Everything is under control
• 他言無用
  (exp) Not a word to anyone
  Mum's the word
• 長居無用
  (exp) There's no point in staying (here) any longer
  There's no point in prolonging a (the) visit
  There's no point in extending one's stay
• 天地無用
  (n) this side up
• 問答無用
  (n) there being no use in arguing (about it)
• 無用の長物
  (n) useless object
  deadwood
  white elephant
  boondoggle