The best replacement for void is voidable.

The best alternatives to void are rated as following:
★★★★★  voidable
★★★  devoid
★★  voided
★★  bandos
★★  armadyl
★  refund
★  voidable contracts
★  voidable contract
  funktion one
  ravager nocturne
  black d'hide
  unenforceable
  int main
  dragonhide
  troll
  null
  void
  karils
  d'hide
  slayer helm
  invalid
  shadow isles
  sentry
  focus sight
  avoid
  spectre
  not to void

Your alternative for void is not listed? Suggest!
Speaking about void, one probably shouldn't forget about return c++.

Other search terms related to void and their ratings are:
★★★★★ return c++
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void
voidable
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