There is just a thin line between an investor and a common man. An investor knows and understands the basic principles of investing into any project and also understands the risks associated with any type of investment but for a common man, he knows about investment but do not really understand basic principles of investing and also know when to invest and when not to invest.
That is because the primary motive of investor is to put his money into something that helps him generate wealth and that is why he explores new venues and gains knowledge about them, whereas a common man is more inclined towards saving his money, not interested to know anything about how can he invest the same.