Q: I hear many politicians vow to “redouble” their efforts. When did this become an acceptable term and what does it literally mean—to quadruple one’s efforts?
A: The verb “redouble” has been an acceptable term since the mid-1400s, when it did indeed mean to quadruple.
But today “redouble” generally means to double or increase greatly, or to double an opponent’s double in bridge.
When English borrowed the term from Middle French in the mid-15th century, it meant to double for the second time or to double repeatedly.
The earliest example in the Oxford English Dictionary is from The Reule of Crysten Religioun (circa 1443), in which the English prelate Reginald Pecock writes that one should “double þis and ȝitt redouble it” (double this and still redouble it).
Although this sense of “redouble” isn’t seen much now, the OED does have a citation for the usage from the January 2003 issue of Wired magazine:
“Even worse are the dupers–counterfeiters who look for software bugs that let them double and redouble their gold on command, turning a single piece into into billions with just a few mouseclicks.” (We’ve expanded the Oxford citation.)
By the late 15th century, “redouble” was being used in the looser sense of “to increase, multiply; to intensify,” according to the OED.
The dictionary has a questionable 1473 citation from the writer-printer William Caxton as well as this definite example from Caxton’s 1490 translation of Virgil’s Aeneid: “Redoublen her sorowes and her trystesses enforce more vpon her.”
The looser sense of “redouble” is similar to the usage in Middle French and Old French, where redoubler could mean “to continue with greater intensity” or “to multiply (something) by two,” according to Oxford.
Although “re-” often has the sense in English of doing something for a second time, the OED notes a “loss of distinct meaning” for the prefix in some English words and even earlier in some Latin terms.
(In a recent post, we discussed a question about a similar subject, the apparently unnecessary “re-” in the word “reduplicative.”)
In other words, it’s not at all surprising that a politician would now use the verb “redouble” to mean merely to double or to increase greatly.