Hello and welcome to Blade forums!
I believe I can answer your questions. Georgia posts all its most current laws online via LexisNexis, but because that site doesn't allow direct linking to individual laws, you may have too look for them via search. The site is here:
http://www.lexisnexis.com/hottopics/gacode/ I will provide statute numbers where applicable.
The main thing Georgia did recently is pass what is called
preemption. This means that local knife laws at the county and city level are void, and all must follow state law instead.
1. The phrase "designed for the purpose of offense and defense" only applies to
large knives with blades 5.5" or greater. For any knife that has a smaller blade than 5.5", it doesn't matter if it is "for offense or defense." (Source: § 16-11-125.1. Definitions.) It is legal to carry
any knife (folder, fixed blade, switchblade, butterfly) without permit if the blade is under 5.5" (Source: § 16-11-126)
2. No explicit definition exists in the law or in case law. However, I would contend the meaning is rather obvious. If the knife is designed to be used for combat (dagger, bayonet) and is not a knife that is made for a utilitarian task (such as a cooking knife or machete), then it would meet this definition. But again, only matters if it is longer than 5.5" (Source: § 16-11-125.1. Definitions.)
3. Georgia's law does not care if weapons are concealed. If carry is illegal, it's illegal open or concealed. If it's not illegal to carry it, concealed is fine and indeed recommended. (Source: § 16-11-126)
4.
Irrelevant of the laws on knives. You are talking about self-defense, which is a complex matter wherein every single situation is judged individually and all evidence is weighed. This is a universal concept all across the US. This much I know from reading knife-related assault and self-defense cases: Using a knife is considered
deadly force. There is no practical way to use a knife in a non-lethal manner that is effective, because even small stabs to unassuming areas of the body can be fatal. Thus if you use the knife against a person who is unarmed and alone, you could be charged with assault or murder even if he/she was the instigator. The only cases I have see where a knife was used against an unarmed person and it was ruled self-defense were where the victim was pinned to the ground and being choked or punched by an assailant on top of them, wherein the victim stabbed and killed them because it was their only means of surviving the encounter.
