adj.不需要的；無用的

Banning smoking would save needless deaths. 禁止吸煙會免除不必要的死亡。

If one is enough, a second although useful is needless. 如果一個夠了，那么第二個即使有用，也是不需要的。

Needless to say, he kept his promise. 不用說，他信守了他的諾言。

Needless to say, learning without thinking is useless. 不用說，學而不思則罔。

adv.毫無必要地