Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
absent (adj., prep.)
The adjective means “not present.” The preposition means “lacking, in the absence of, without.” It was once limited mainly to rather Formal legal writing but now has much wider and more general use, especially in introductory (albeit somewhat formal) clauses: Absent better news from the Middle East, the market will almost certainly continue its decline.
