From Longman Dictionary of Contemporary Englishat your bestat your bestBESTperforming as well or effectively as you are able to At her best, she’s a really stylish player. He was never at his best early in the morning. → best
Examples from the Corpus
at your best• At his best, he's one of the most exciting tennis players in the world.• This recording captures Grappelli at his very best.• The answer, in brief, is the method of empirical inquiry, at its best the method of science.• But like Natalie Merchant, Cerbone is at her best when composing character sketches.• The Machine is at its best in primaries, but Daley was taking no chances.• Still, quarterbacks are not at their best when their throwing motion is impeded.• Augusta was not at her best yesterday on a drab, grey day.• The early 1960s showed such policy at its best.• The formal work of the House is often seen at its best in committee.• And if I sometimes see them at their worst, I sometimes see them at their best as well. 