Answer:
Based on my understanding within those words, the words unwise and foolish aren't that exactly same. Being unwise simply means not wise, or having defectives in thinking or in terms of wisdom. On the other hand, foolishness refers to lacking good sense or judgement; in other words, a foolish person may not be able to decide what's right or wrong.
(If you want to add)
However, those words can be interchangeably used as they are almost the same.
