The phrase "astonishing decision" is correct and usable in written English.
You can use it to describe a decision that is surprising or remarkable in some way.
Example: "The board's astonishing decision to approve the merger left everyone in the room speechless."
Alternatives: "remarkable choice" or "surprising verdict."
It was an astonishing decision: who knows the cost to England?
Ultimately, Shackleton made what Worsley considered "the most selfless and astonishing decision ever in the history of polar exploration"—he turned back.
Ultimately, Shackleton made what Worsley considered "the most selfless and astonishing decision ever in the history of polar exploration" — he turned back.
This is largely a self-inflicted wound, worsened by the astonishing decision to allow a fly-on-the-wall documentary of Downing Street's media operation, which was shown the night before the leak of the prime minister's memorandum.
In 1979, having stood and been defeated in his Devon constituency, Thorpe faced trial and, in what was seen as an astonishing decision, the judge believed his case over that of his accusers.
According to Carl Davis, who conducts Chaplin's score of The Gold Rush in London on Saturday, "he made an astonishing decision - to keep City Lights a 'silent' film, that is, without dialogue.
Every spring, like psychotropic daffodils, decorators' show houses break out across the country -- big, popular bulbs of astonishing decision-making for the home that blossom before the public briefly in charitable benefit of local institutions.
This is why the decision to replace him with Avram Grant appears to be one of the most astonishing decisions in the history of football.
The match was an end-to-end affair with some astonishing refereeing decisions littered across the dramatic match.
Generally, the rigorous enchantments and occasional missteps by Ms. Neshat and her company are the result of astonishing creative decisions at the end of the process.
It is astonishing that the decision to go to war, the gravest decision ever facing a nation, is still taken in this country by one person alone, the prime minister, and there is no requirement to seek parliamentary approval.
