"Historical kana usage", a prescriptive method of using kana to write Japanese. Devised in the Edo period by Keichū (契沖) and taught in schools until 1946, it aims to be etymologically faithful and reflects earlier stages of the language (Heian period and earlier).

humanitarian

hostile takeover

experimental study

impractical; unpractical

unproductive

secondary

(linguistics) a specific historical consonantal shift of the Japanese language during the Heian Period, wherein many word-medial /f/ sounds changed to /w/ sounds

pedestrian-only street, pedestrian mall

(literally) above heaven and under heaven / (figuratively) the whole world or universe