What is the meaning of Up_and_down?

upward and downward, alternately.

alternately forwards and backwards along a path

staunchly, unwaveringly, obstinately

In various places, e.g. in a country.

Vertical; perpendicular; said of the cable when the anchor is under, or nearly under, the hawse hole, and the cable is taut.

plain; downright

Source: wiktionary.org