(linguistics) diachronic

(linguistics) synchronic

unscientific

accidentally (unexpectedly, unintentionally)

unsociable; retiring; solitude-loving

palliative care

asymmetrical (not symmetrical)

surreal, surrealist, surrealistic

unrealistic

"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).