If you’ve ever used the Flinders St toilets then you’d know that calling the odour emitted from thousands of caffeine-loaded commuters’ ablutions an “unpleasant aroma” is putting it lightly. Lightly and politely. Such an expression would once have been utterly contradictory, as aroma once meant “a sweet odour” in Latin, which itself was ultimately descended from Greek when it meant “spice, seasoning”. It’s not just aroma whose sweet meaning has soured. Think of the words you might use to describe any unpleasant olfactory observation: stink, stench, smell. These words were once 100% neutral. In Old English, the phrase swote stincan, “sweet stink (i.e. smell)” is attested but it sounds ridiculously oxymoronic to our modern ears.
In fact, think of all the words for different types of smells that you know and order them in your head. Your list probably looks something like this: stench, stink, smell, odour, aroma, scent, perfume, fragrance. Your ordering may differ slightly from mine, but the fact is that you have roughly ordered these words according to the time since they have entered the English language. Stink and stench have been in the English language as far back as is traceable, and were actually originally the same word (compare with drink and drench). All the words from odour onwards were borrowed into English from French or Latin after the 13th century, with fragrance being the most recent in the mid 17th century.
What has caused the connotations of these formerly fine words to deteriorate and decay? Well, it turns out that a bad smell is not an appropriate conversational topic, so we must cover the concept with a polite word or expression, a sort of linguistic deodorant that makes it palatable for our listeners. These “linguistic deodorisers” (so dubbed by Monash’s resident linguistics professor, Kate Burridge) are called euphemisms, and we spray them liberally on our language to cover up taboo topics. However, after a while the deodorant stops fooling anyone, and we must find a new expression to fill the euphemism-can, and so new words are borrowed or old words with more pleasant meanings are co-opted to take its place. This constant rate of euphemism replacement has been called the “euphemism treadmill” by linguist Steven Pinker. The sad fact is that after running a while on the euphemism treadmill, any word is going to start to stink.