Menacing is the criminal charge that arises if you "knowingly" place someone "in fear of imminent serious bodily injury." In other words, you try to make someone believe they are going to get seriously hurt right now – not at some future date. In Colorado, the District Attorney must prove that you knew your actions were likely to make the person afraid, even if the person was not actually afraid.
Historically, in Colorado, it was necessary for the prosecutor to prove that you intended to cause fear. Now, however, the prosecutor only needs to prove a "knowing" state of mind, in other words, that you knew that you were likely to cause fear.
Menacing can be charged as a Class Three Misdemeanor (M3), or as a Class Five Felony (F5) in Colorado. It becomes a felony when it involves the use of a Deadly Weapon. It does not matter if the weapon is real. You can commit menacing with a toy gun, if you handle it in such a way that you make the person believe it is real. You do not have to point the weapon (real or not) at someone to be found guilty, simply holding it "in a manner that causes the other person to fear for his safety" will suffice. You can also be charged with Menacing with a Deadly Weapon even if you do not have a weapon! Simply telling
someone that you are armed may result in a Menacing charge.