Of the highest rank, or peak of excellence(adjective)
In the highest division(adjective)
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Use "top-flight" in a sentence
"Unlike China and India—two other billion-person markets—Africa generally lacks the top-flight universities to feed young talent to companies that are now investing on the continent."
"Simon's move to gain control is unusual because top-flight U.S. malls rarely change hands."
"This is one of medicine's dirty secrets: Most results, including those that appear in top-flight peer-reviewed journals, can't be reproduced."