"highly vague" is a correct and usable phrase in written English
You can use it when you want to emphasize how a statement or description is unclear or imprecise. For example, "Her instructions were highly vague, and it was impossible to know what she wanted us to do."
"The consistency running through the images is partly because my father was the only one making the main conceptual and creative decisions," says Jenny. "He didn't consider highly stylised, vague, imaginative or fanciful illustration appropriate, even for fiction like the fairytale series, Well-Loved Tales".
By that I don't want to say that the people on the retreat were especially damaged, but you don't book yourself into a highly experimental, vaguely legal, and potentially dangerous drug therapy retreat because you're tired of package holidays.
But the statement is a vague, highly selective catchall.
"The highly general and vague nature of these questions would unfairly require the seller to speculate as to precisely what the questions are asking and how they should be answered," Mr. Pataki said.
Because no one can agree on what constitutes blasphemy, laws that attempt to ban it are themselves vague, highly prone to arbitrary enforcement and are used to stifle everything from political opposition to religious inquiry.
Highly technical with vague phrasings, these error messages often leave users more confused than enlightened.
As with Herbalife, Nu Skin and similar platforms, the pitch to prospective Primericans is a vague, highly emotional appeal that suggests not only financial rewards, but the revitalization of a lifestyle.
But for the moment it's a highly noticeable, and vaguely fun, tech-fashion statement.
In his re-analysis of prior samples of gay men, Weinrich (1978) noted, "As one moves from prisoners, to soldiers, to a clinical sample, to unmatched nonclinical samples, and finally to carefully matched nonclinical samples, the results move from highly mixed, to vaguely positive [gay men scoring higher in IQ], to significantly positive, to nearly ironclad" (p. 286).
Thomas's adjectives, sweet, strange, dear, etc, and the superlatives, dearest, oldest, are catch-all words – vague but highly emotive.
It is, however, important for them to invest in regulators, whose own career prospects are increasingly tied to their ability to advance rules that are both vague and highly technical, as this increases their value both within government and to potential private employers.
