Exacerbate and exasperate form a tidy pair, not because they travel together (they seldom do) but because they are like siblings that closely resemble each other, so much so that one is often mistaken for the other. The fact that one is a bit better known than the other exacerbates this, and exasperates sticklers. Consider these quotations:
Two injuries on the head; one of which was so much exasperated by his subsequent fatigues.
Not considering that the law should be exasperated according to our estimation of the injury.
This visionary opulence for a while soothed our imagination, but afterwards fired our wishes, and exasperated our necessities.
They don’t seem… quite right, do they? In every one, the word that would sound better to my ears, and probably to yours, is exacerbate. But before I tell you where the quotes are from – which I will do in the fullness of text – I should say that there are exasperating circumstances for them. Or, well, I’m sure you’ll understand.
First, though, have you ever stopped to look at the parts these words are made of?
Each one plainly has a root with a prefix and a suffix, and the same prefix and suffix for each: ex-[root]-ate. The -ate is no big problem; it makes verbs of things, to indicate doing, or inflicting, or making. The ex- is of course familiar, but it can be confusing. It doesn’t mean ‘former’ here, as in ex-president; it uses its Latin sense of ‘out’ to intensify, just as the out in outdo does. You could say it means ‘way’ or, um, ‘as all get out’.
That leaves the roots. Do they look familiar? You may recognize them from their roles in acerbic and asperity. The acerb- comes from Latin acerbus, ‘harsh, bitter, rough’, from acer ‘sharp’. The asper- comes from Latin asper, ‘rough, harsh, bitter’. And yet, somehow, the two are not etymologically related.
So anyway, one of them means, in its origins, ‘make really harsh, bitter, or rough’, while the other means, in its origins, ‘make really rough, harsh, or bitter’.
Exasperate, I should say, has been in the language apparently about a century longer than exacerbate; the one showed up in the 1500s, the other in the 1600s. And exacerbate is perhaps slightly less used, but it has always been used as we use it now: to mean ‘embitter, aggravate, irritate’. Or, as Samuel Johnson put it in his 1755 dictionary, “To imbitter; to exasperate; to heighten any malignant quality.” Meanwhile, exasperate has…
Say, what did Johnson say back there?
“To imbitter; to exasperate; to heighten any malignant quality.”
I see. Um, what was his definition of exasperate?
As it happens, since exasperate is the older and more used word, he gives it more definitions (as it does in the Oxford English Dictionary, among others) – these three: “To provoke; to enrage; to irritate; to anger; to make furious”; “To heighten a difference; to aggravate; to embitter”; and “To exacerbate; to heighten malignity.”
Well, that would be why Johnson felt quite comfortable writing “This visionary opulence for a while soothed our imagination, but afterwards fired our wishes, and exasperated our necessities,” as I quoted above. And why John Milton (yes, the famous one), in 1643, could write “Not considering that the law should be exasperated according to our estimation of the injury.” And William H. Prescott, in his History of the Conquest of Mexico, could write “Two injuries on the head; one of which was so much exasperated by his subsequent fatigues” – in 1843.
Now, Oxford assures us that the third sense as defined by Johnson is currently “obsolete.” But it wasn’t at the time, and it seemed perfectly sensible in view of the word’s analytical sense.
However, most people who use these words these days don’t know where they come from, and for that matter aren’t aware of knowing much Latin at all. So the words are free to come unmoored from their origins. But they aren’t drifting too far. Exacerbate hasn’t really drifted at all, in fact, no doubt helped by the fact that it’s not used so often (partly because ‘worsen’ serves the turn well, and perhaps partly because it sounds a bit like a word many people would blush to say in polite company).
As to exasperate, it has not only drifted away from that sense – well, we don’t need yet another word for that, really – it has also drifted into calmer waters. Whereas exasperated once plainly meant ‘embittered’ or ‘enraged’ and could be used as Benjamin Franklin did, in a context such as “The poor are … exasperated against the rich, and excited to insurrections,” now it’s more on the order of a mother’s exhaustion with her intransigent offspring, or a customer’s impatience with a company’s endless phone maze and hold music.
Or a stickler’s feeling towards someone who uses exasperate where exacerbate is called for: peevish aggression wearing the mask of injury. Because, as usual, when language is used to filter out the “wrong sort,” it’s a pretty fine filter, calibrated to small distinctions – including ones that haven’t always been real distinctions at all. And such weaponization of language only exacerbates the hair-splitting.