Meanings of be no slackness in английском

There must be no slackness.

It was above all essential that there should be no slackness: "Work," said the Prince, "must be work."

There was no slackness in his watch; he kept us up to scratch.

In fact, about him was no slackness, no sprawling abandon of the native in relaxation; but always a taut efficiency and a never-failing self-respect.