Q: Why do we say “president-elect” rather than “president-elected”? In other words, why is the infinitive used here instead of the past participle? Granted it sounds better, but that may be because we are accustomed to it.
A: Since the early 15th century, the word “elect” has been used as an adjective meaning picked out or chosen, according to the Oxford English Dictionary. It’s derived from the Latin word eligere (to pick out or choose).
In fact, “elect” was used in this sense for a century and a half before the past participle “elected” was used adjectivally to mean chosen, according to OED citations.
Here’s the OED‘s first published reference for the adjective “elect,” from The Chester Plays, a collection of miracle plays written around 1400: “Man, I saye againe, which is his owne eleckte, / Above all creatures seculierlye seleckte.”
And here’s a citation from The Cronicles of Englond, published by William Caxton in 1480: “Saul … was a good man and elect of God.”
In the 17th century, people began using the word “elect” alongside a noun (as in “bishop elect,” “bride elect,” and so on), to refer to someone selected for a position.
John Milton used this construction in Paradise Lost (1667) when he referred to the Israelites as “the Race elect.”
The earliest example in the OED of “elect” used in something akin to our modern political sense is this quotation from a 1742 translation of Cicero: “Sextius was one of the Tribunes elect.”
In short, “president-elect” has a long heritage.