a. 必要的, 需要的

[ adj ]
necessary for relief or supply
<adj.all>
provided them with all things needful

Needful \Need"ful\ (n[=e]d"f[.u]l), a.
1. Full of need; in need or want; needy; distressing.
[Archaic] --Chaucer.

The needful time of trouble. --Bk. of Com.
Prayer.

2. Necessary for supply or relief; requisite.

All things needful for defense abound. --Dryden.
※ -- {Need"ful*ly}, adv. -- {Need"ful*ness},
n.