Adjective

• 1. having no justifying cause or reason;

  "a senseless, causeless murder"

  "a causeless war that never had an aim"

  "an apparently arbitrary and reasonless change"

• 2. having no cause or apparent cause;

  "a causeless miracle"

  "fortuitous encounters--strange accidents of fortune"

  "we cannot regard artistic invention as...uncaused and unrelated to the times"