"it is nebulous" is correct and usable in written English.
You can use it when referring to something that is unclear, indistinct, or vague. For example: "The future of our company is still nebulous; we don't know what it will look like yet."
As is often the case in provincial politics, their dispute was as multipronged as it was nebulous.
"I was following the debate in the house and I can't see where the British parliament is heading at and that's why I was saying it's nebulous," he said.
Sometimes everything seems flat, like a pattern in a carpet; at other moments, it's nebulous and made of stars, or biological, as though the whole universe were built from fingers or eyeballs.
The actual value of the idea, certainly at the beginning, was rather vague and it was nebulous and it was very difficult to articulate.
One problem in finding an answer is that "al-Qaeda" is nebulous: it is at once a secret organisation, a network of militant groups and a diffuse social revolt.It includes a cluster of leaders around Osama bin Laden and Ayman al-Zawahiri, thought to be sheltering in Pakistan's wild frontier after being evicted from Afghanistan.
Furthermore, it can make something that is nebulous or fuzzy seem stable, mechanical and precisely defined.
At this point the form that the WAC platform will take is nebulous, so it's hard to make predictions.
Om is nebulous, and it's vague.
Agreed, it might be nebulous: polls suggest the public don't get it and many Conservative candidates confessed themselves equally at a loss when it suddenly landed on them from on high at the start of the general election campaign.
Everything about Abrams is nebulous.
