From Longman Dictionary of Contemporary Englishneedfulneed‧ful /ˈniːdfəl/ adjective old use MUSTnecessary needful expenditure
Examples from the Corpus
needful• It was not spoken of but drawn upon when it was needful.• The proposed discount will go only a certain way towards doing what is needful.• He might be seen returning, and it was needful he should come by the way he would have taken to Longner.• To effect the separation it was needful that the particle size was more or less the same.• It will be needful to find them, Master Hussey. 