"make vague" is correct and usable in written English.
To use it, it can be used to describe an action. Example: The witness's statements were deliberately made vague in order to protect their identity.
$200,000 to study why political candidates make vague statements.
"It's wrong, when thousands are being molested, to just make vague promises".
Often the psychics make vague, generalized remarks that could fit into many people's lives.
It was not until 3 days after the attacks that Colonel Qaddafi began to make vague references to casualties.
To build a consensus you make vague statements that everybody can interpret any way they want to.
It was not until 3 days after the attacks that Colonel Qaddafi began to make vague references to casualties..
A clutch of songs from 1992's Countdown to Extinction album make vaguely anti-war noises while revelling in the imagery.
Mr. Humphrey said Sandoz had made vague promises.
Then she makes vague, generous noises about a possible successor.
The authorities are dragging their feet, making vague promises".
It initially made vague threats about working with law enforcement to stop "product tampering".
