You asked:

what means sinister

  • "Sinister"'s synonyms include "baleful", "black", "dark", "forbidding", "menacing", "minacious", "minatory", "ominous" and "threatening".
  • "baleful"

  • "black"

  • "dark"

  • "forbidding"

  • "menacing"

  • "minacious"

  • "minatory"

  • "ominous"

  • "threatening"