The most common and most likely answer to this crossword clue is the 11 letter word GENERALISED
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More clues leading to the result GENERALISED
Buddy explains!

The straight part
We know that "vague" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vague = generalised.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GENERALISED mean?
GENERALISED verb- To speak in generalities, or in vague terms.
- To infer or induce from specific cases to more general cases or principles.
- To derive or deduce (a general concept or principle) from particular facts.
- Made more general, less specialized.
- Spread throughout or affecting the entire body or body part.