Mark Peters on the origins of “the truther movement:”
Trutherism may never be more than a joke, but that joke has been extraordinarily successful — so successful that “truther” has spawned several other names for similarly outrageous movements, catching on as a word for any kind of conspiracy-lover or true believer, giving great relief to worn-out terms such as “conspiracy nut” and “kook.”
I’m not sure when the “er” suffix first caught on — or why words that end in “th” have been so “er”-worthy — but Leslie Savan thinks the trend may go back to “grassy-knoller” and “mooner,” as JFK and no-moon-landing cranks are called, respectively. Here, Savan, sums it up: “Call it a vast linguistic conspiracy: proponents of the major conspiracy theories of the day — the truthers, the birthers, the deathers — share a suffix that makes them all sound like whackdoodles.”
The broadening of “truther” is still in-flux and newish, but it’s a well-worn path followed by many other words. “Enthusiasm” referred to a God-possessed frenzy before it came to mean a general sense of excitement. “Lousy” meant “lice-y” before it grew to mean crappy. The first volunteers were specifically military, well before volunteers turned up in animal shelters and soup kitchens. More recently, “blog” morphed from meaning a whole website to a single post. Language doesn’t change as quickly or catastrophically as the weather, but its evolution is equally unpredictable and unstoppable.