expression, noun which may take the genitive case particle 'no', adverb
as much as possible; to the best of one's ability
A somewhat formal or literary expression meaning 'to the fullest extent one can'. Often used in set phrases like 能う限りの努力 or 能う限り早く. The modern equivalent is できる限り.
See also: できる限り
I will spare no effort in giving as much assistance as I can.
I will reply as soon as I possibly can.
Standard kanji spelling using the classical verb 能う (あたう).
Mixed kana-kanji spelling; the verb part is written in kana.
From the classical verb 能う (あたう, 'to be able') + 限り (かぎり, 'limit'). The verb 能う is the classical equivalent of modern できる.