noun, adverb
from now on; henceforth; hereafter
Archaic literary expression. In modern Japanese, 今後 (こんご) or これから is used instead.
而今而後は心を入れ替えて生きる所存にございます。
From now on, I intend to live with a reformed heart.
A classical Chinese-derived compound (而今 'now' + 而後 'after this'). The exact historical path into Japanese is uncertain; it is now an archaic literary expression.