There may be a lack of money. There may be a lack of skilled labour. There may be a lack of raw materials. There may be a lack of equipment. There may be a lack of transport or communication facilities.
The lack of resources may be general, as in some developing countries. Or the lack may be specific. For example, the lack of IT-trained people, even in a highly developed country.

Teachers in school may lack teaching materials. Hospitals may lack basic pharmaceuticals or even nurses.

It is not difficult to pinpoint situations where there is a manifest lack of resources for what needs to be done.

It is possible to have a "wish list" of resources which is far in excess of what is really fundamental. This may be nice but unrealistic. At he same time there is a baseline below which resources should not fall.

Missionaries used to make do with very scarce resources and ingenuity can do the same. Nevertheless, a serious lack of resources makes for a very difficult environment.