The origin of curmudgeon is not known, but that has not stopped a couple of explanations, neither with any real evidence supporting them, from circulating.
What we do know is that appears as early as 1577 in Richard Stanyhurst’s A Treatise Contayning a Playne and Perfect Description of Irelande:
Such a clownish Curmudgen.
One of the unsupported contentions is that it is a variation on cornmudgin. The Middle English muchen means to hoard. So a cornmudgin is someone who hoards grain. The problem with this explanation is the only known use of cornmudgin is from Philemon Holland’s Livy’s Romane Historie of 1600:
The fines that certeine cornmudgins [frumentarios] paid, for hourding up...their graine.
Unfortunately, for this explanation is that curmudgeon is older than cornmudgin. It is more likely that cornmudgin is pun, playing on curmudgeon.
The second is from Samuel Johnson’s 1755 Dictionary, in which Johnson wrote:
curmudgeon n.s. [It is a vitious manner of pronouncing coeur mechant, Fr. an unknown correspondent.]
Coeur mechant means bitter or evil heart in French. Johnson’s Dictionary is a historically important work, but he got a lot wrong and his etymologies are often particularly suspect. This one from the unknown correspondent is one such case. It is a reasonable guess, but it’s not supported by evidence.
Johnson’s etymology has also given rise to one of the worst lexicographic howlers in history when in 1775 lexicographer John Ash gave the etymology as “from the French coeur, unknown, and mechant, correspondent.” To be fair to Ash, Johnson’s wording is ambiguous, but he should have checked the translation.
Copyright 1997-2015, by David Wilton