General synonyms:
* Indefinite: This is a very close synonym, meaning not clearly defined or stated.
* Ambiguous: This implies that something can be interpreted in multiple ways.
* Unclear: This simply means that something is not easily understood.
* Fuzzy: This implies a lack of sharpness or precision.
* General: This implies a broadness or lack of specificity.
More specific synonyms:
* Imprecise: This implies a lack of accuracy or detail.
* Abstract: This implies that something is conceptual or theoretical, rather than concrete.
* Elusive: This implies that something is difficult to grasp or define.
* Nebulous: This implies that something is hazy or indistinct.
* Obscure: This implies that something is hidden or difficult to understand.
The best synonym to use will depend on the context of the sentence.