私自监禁

【法】 extralegal imprisonment

私自的英语翻译：

privately; secretly; without permission
【经】 without authorization

监禁的英语翻译：

prison; put into jail; arrest; durance; incarcerate; pinfold; pound
take into custody; imprisonment; incarceration
【法】 bondage; committal; confine; confinement; detainment; duress; imprison
imprisonment; incarcerate; incarceration; lay by the heels; pen
restraint