The phrase "hallmark achievement" is correct and usable in written English.
It can be used to describe a significant or distinguishing accomplishment that stands out as a mark of excellence.
Example: "Winning the Nobel Prize was a hallmark achievement in her career as a scientist."
Alternatives: "notable accomplishment" or "distinguished success."
His hallmark achievement will remain his dramatic success in reducing crime and giving New Yorkers the feeling that their city is safe and governable.
ACCURACY -- The commercial conveys what Mr. Giuliani considers to be a hallmark achievement of his tenure: the creation of hundreds of thousands of new jobs in New York City.
Mr Boehner's Republicans are pushing to repeal a sitting president's hallmark achievement a year after he was re-elected.
Decertifying the Iran nuclear deal ― a hallmark achievement of the Obama administration in 2015 ― would undermine an international agreement reached by all five permanent members of the U.N. Security Council and Germany.
The stakes are high: Failure to strike a deal could bring down the government of Germany, Europe's wealthiest economy, and potentially spell the end of free movement within the EU, one of the bloc's hallmark achievements.
This was the hallmark of Mr. Levine's achievement.
helps your child link effort and achievement, a hallmark of the growth mindset.
"One of the hallmarks of a great intellectual achievement is that it brings into a common framework a wide variety of seemingly different problems," Mr. Blinder said.
Some experts say that incremental achievement has been the hallmark of the European Union and that perhaps the real failure of the Nice meeting was to have raised everyone's expectations.
"Today's title win is a truly great achievement by a club whose hallmark has been success throughout its proud history," said Whyte.
Obama does recognize the pain that afflicts too many Americans, but he should also be the champion of an agenda of optimism, aspiration and achievement that will be the hallmark of a second Obama term.
