Well, in that case anything is a weapon, including a pencap or blanket. The boundary is drawn here: A weapon is designed specifically for hurting, maiming, destroying, et cetera. Like a gun, or a pistol. They also have other uses... you can hammer in a nail with a pistol. But that does not make it a hammer. Since our bodies were not "designed" (not designed at all, actually) for killing, maiming, and destroying (at least not solely) then we are not weapons...
I think that modern propaganda is most eavil weapon.U all sayed that human mind can be weapon,and that most off ppl r good by nature,but something need to trigger the killing instinct.Whell,there come medias....
IMO it would be biological weapons. They do not discriminate and kill anyone that is infected. The mode of death is usually painful and includes much suffering and finally they can potentially pose a threat to the future existence of all mankind.
I think the human, mindless or not is the most evil weapon of all. You just have to turn on the tv news to see, deaths, injuries, etc as the result of human minds, Any tool, not designed as a weapon may still be one. If you consider the old fashioned kung fu type weapons, most of them are originally farm implements. Any thing can kill, hammer, ice pick. anything.
A neutron bomb releases enormous quantities of neutrons and a relatively small amount of blast energy. The highly energetic neutrons are fatal to living organisms, but do much less damage to structures without lingering radiation. Baiscally, it kills people without destroying property.