not clear or exact
nebulous - unclear
Something ‘nebulous’ is vague or indistinct. While the word was originally used in relation to misty or foggy conditions, it has since been adapted to express something, such as an idea or plan, that is unclear or not fully thought out. It is more commonly used in a professional context.
We need to put together something more concrete. The plan is too nebulous at the moment.
The politician did not set out any clear proposals in her speech, she just made some nebulous references to changes that could be made.
The rules are quite nebulously defined, which is likely to lead to conflict and confusion.