Used as an exclamation, when something bad has, is, or was happening.

Naive, stupid. Can't tell one's ass from first base; see Shinola.

This word is used to describe not understanding or knowing what is going on.

For many, especially in the Southern US, it means the person referenced is an ignoramus . That is, if the person had their shoes shined. they could easily be fooled by the shine man who could just as well put shit on their shoes as shoe polish