Overanalysis is exactly what it means, only in this context it has to do with trading
It simply means the process of second-guessing yourself over and over again, trying to get the perfect validation from the market(looking for the perfect trading opportunity), but the truth is that the perfect validation doesn't exist and because most traders fail to realize this, they keep on analyzing and analyzing and analyzing and in the process end up missing out on most opportunities that the market presents to them
It's also synonymous to analysis paralysis: Meaning the act of not being able to act on opportunities because of too much analysis or info