The term "toothbrush killer" refers to a specific method of murder where a toothbrush is used as a weapon. This method gained notoriety due to its unusual and brutal nature, often involving the use of the toothbrush's sharp edges or the handle to inflict harm. This phrase is also associated with certain criminal cases, where individuals have committed violent acts using everyday items. The concept highlights the potential for ordinary objects, like a toothbrush, to be transformed into tools of violence in extreme circumstances.