ninety-nine times out of a hundredidiomPart ofhundredninety-nine times out of a hundredninety-nine times out of a hundred — idiomidiom1. Almost always or in nearly every instance.1.idiomDefinitionAlmost always or in nearly every instance.ExampleNinety-nine times out of a hundred, the train arrives on time.Sara chooses the salad option ninety-nine times out of a hundred.