Approach anxiety is anything that would cause you not to approach a target. It's your subconscious telling you what you need to hear to not approach. Not approaching isn't just being in a venue and not opening sets. It is also not going out when you planned to, or or going home when you get there because you can't find a parking space (yes, I've done that.) If you don't go up to sets because you don't know what to say: approach anxiety. If you don't open because she looks uninterested: approach anxiety. If you don't go out because you haven't done it in a while: approach anxiety.
There are standard ways to deal with this. They are easy to find so I am not going to go into fixing the problem.
Just remember, if you ain't talking to targets for WHATEVER REASON, it's approach anxiety. React appropriately.
So, if you talk to me about how the material doesn't work for you, or how you don't know any good openers or DHV stories and therefore don't open, or you haven't done it for a month and don't know if you still have it, it's approach anxiety. No excuses guys. APPROACH!