The big news of the day is that Donald Trump fired Secretary of State Rex Tillerson—and all the headlines are describing his ouster or running some language of him being ousted. Where do this journalistic go-to term for “dismissal” come from?
An obstinate ouster?
Oust enters English in the early 1400s from the Anglo-Norman French ouster and French oster before it. The verbs meant “to take away, deprive, or eject” and made their way into Law French, the language used in English courts well into the 17th century.
Before a judge, to oust was originally “to dispossess someone of or eject them from a property.” The Anglo-Norman French infinitive form of the word, ouster, was used so much for such an act of dispossession or ejection that it became its own noun in English.
So, the -er in ouster isn’t like the -er in heater or doer. It’s the French infinitive marker.
From their use in Anglo-Norman French for matters of feudal law, English also “nouned” other French infinitives forms: waiver, retainer, disclaimer, merger, and rejoinder. Such noun uses in French isn’t in uncommon (e.g., le manger), and that the words resembled the widespread and native -er agentive suffix in English probably helped them take root in the language.
Over time, oust and ouster drifted away from their strict legal senses. By the late 18th century, we can find oust for “expel from a position” and ouster for an “expulsion.” Currently, the Oxford English Dictionary gives the earliest citation it has for this oust to Thomas Jefferson, the first official Secretary of State of the United States.
In a 1787 letter to John Jay (the first acting Secretary of State), Jefferson says of the embattled Archbishop of Toulouse: “An intrigue is already begun for ousting him from his place.”
Behind the French ouster/oster is the Late Latin obstare, “to remove, take away, prevent from,” an extension of its original meaning of “to stand in the way, hinder” (ob, against, stare, to stand; obstinate is related)—which is precisely what Trump, apparently, thought Tillerson was doing to his agenda.