Here are some synonyms for improvident:
* Careless
* Thoughtless
* Reckless
* Short-sighted
* Unwise
* Wasteful
Here are some examples of how "improvident" might be used in a sentence:
* "The improvident young man spent all of his inheritance on frivolous things and ended up broke."
* "Her improvident spending habits led to a mountain of debt."
* "The company's improvident investment decisions resulted in financial ruin."
Essentially, someone who is improvident is not thinking ahead and is likely to make decisions that will lead to negative outcomes in the future.