Legally, none whatever; there's no threat (as defined by law) until the pursuer does one or more of the following: (1) makes an unlawful threat of violence, such as "I'm gonna kill you/kick your ass/etc" (2) makes an unlawful demand, such as "Give me your wallet/money, watch, etc." (strong arm robbery) , (3) initiates an unlawful touching/punching/grabbing/etc. (battery, unlawful restraint), or (4) unlawfully produces/presents a weapon.
What is considered lawful and unlawful in regards to producing/presenting a weapon in the state of Florida?
Uptown, that's actually an excellent question. I know what the law ordinarily is in most states, but a number of Florida statutes (their arrest statute, for example), are simply written differently. In most places, "unlawful pointing/presenting of a firearm" would be drawing it (without necessarily firing it) as a threat, in a situation that was something other than self defense, or defense of the life of another, stopping a forcible felony in progress, or in some states, making a lawful arrest. (I add that last because in my state, the statute that allows use of deadly force to protect one's home, stop a felony in progress, etc. is actually under a "power of arrest" conferred upon "any citizen of this state" under certain specified circumstances). I know, that certain concealed carry laws (in states which do not allow open carrying), provide that merely showing the holstered weapon
intentionally is a violation of the law (unless one is ordered to by a law enforcement officer, of course). If I had to guess, I'd assume the Florida law for civilians authorized to carry concealed would be something like the first part of the above, but I have no idea how the Florida law is worded, and as we've seen with the "Stand Your Ground" self defense statute there, the wording can make a lot of difference. It may be a moot point in this case, because to this point, we have not yet seen any evidence that Zimmerman intentionally showed his weapon in any way prior to drawing it and shooting Martin (having it inadvertently revealed in the course of a struggle would not itself be a violation of any concealed carry law I've ever seen). That said, there exists the possibility that something we don't know could come to light, and combine with whatever the Florida law says about "pointing and presenting", to be germane to this particular case. We have, after all, had some surprising revelations related to the wording of Florida laws here. Curious are the ways of legislators....