The offing is the near future, in the phrase about to happen. In the offing, changes in the offing, trouble in the offing.
It occurs almost only in in the offing. The origin is nautical and exact: the offing is the part of the sea visible from shore but well out from it, so a ship in the offing is not here yet and is clearly coming — which is precisely what the figurative phrase means.
1nounoffingThe near future, in the phrase in the offing.
“With a new baby in the offing, they started looking for a bigger flat.”
offing is a nearness in time.
Off plus -ing, attested before 1600. The offing is the distant part of the sea still in sight from land.
From off + ing. Attested since before 1600. Early texts also spell the term offin and offen.
Etymology from Wiktionary, CC BY-SA