Nihil obstat is a declaration of no objection that warrants censoring of a book, e.g., Catholic published books, to an initiative, or an appointment.

What does nihil obstat mean in Latin?

History and Etymology for nihil obstat

Latin, nothing hinders.

What is the difference between nihil obstat and imprimatur?

Strictly speaking, the imprimatur is nothing more than the permission. But because its concession must be preceded by the favourable judgment of a censor (nihil obstat: “nothing hinders [it from being printed]”), the term has come to imply ecclesiastical approval of the publication itself.