赤ふあこう

あこう · akou

JLPT N5 i-adjective 連用形

赤ふ is the masu-stem of 赤し — red, crimson, scarlet, vermilion.

Classical Japanese — you’ll mostly meet it in older texts and set phrases

Full entry for 赤い

How it’s built

赤し赤ふ

Masu-stem (連用形). The base for ます, たい and ながら, and the way to link two actions: 書き → 書きます.

This spelling is the version with う (sound change, mostly in polite or older speech).

赤し is a classical japanese conjugation, so it follows that pattern.