Alternative spelling of 紙やすり (“sandpaper”)

timber - trees in a forest regarded as a source of wood. / material wood, (UK) timber, (US) lumber - wood that has been pre-cut and is ready for use in construction.

smooth (surface)

smooth (surface; progress) / calm (water)

needed, necessary

need, necessity

unnecessary

needlessness

necessary evil

necessity (quality or state of being necessary, unavoidable, or absolutely requisite)