1
                           general:: 
                            Phrase(s): rub something out 
to obliterate something by rubbing.  •  See if you can rub those stains out.  •  Rub out the graffiti on the side of the car if you can., Phrase(s): rub someone out 
Sl. to kill someone. (Underworld.)  •  The gunman was eager to rub somebody out.  •  The crooks tried to rub out the witness.
                        
                        
 
                        
                            McGrawhill's American Idioms And Phrasal Verbs
                        
                        
                    
                    
                        2
                           general:: 
                            1. Obliterate or erase by, or as if by, rubbing. For example, Bill was so busy rubbing out the old markings that he forgot to put in new ones. [Mid-1600s] 2. Murder, kill, as in They threatened to rub him out if he didn't pay up. [Slang; mid-1800s]
                        
                        
 
                        
                            American Heritage Idioms