tofu (archaic court-lady slang)
Archaic female court language (女房詞). Used as a secret or euphemistic word for 豆腐 among court ladies. Not used in modern Japanese.
See also: 豆腐
In court-lady language, tofu was called 'okabe'.
The origin is uncertain. It is a euphemistic term from 女房詞 (court-lady language), possibly derived from 壁 (wall) with the honorific prefix 御, but the exact derivation is unclear.