a.

1. 需要的，必需的
   Food, clothing and shelter are needful for the maintenance of health.

   衣、食、住是维持健康所必需的。

2. 【古】贫穷的

n.[theS]

1. 必须做的事
   do the needful

   做必需做的事

2. 【英】【幽】钱
   We're rather short of the needful now.

   我们现在很缺钱。

adj.

1. formal necessary; requisite.
2. dated needy.