curmudgeon
1570s, of unknown origin; the suggestion, based on a misreading of a garbled note from Johnson, that it is from Fr. coeur mechant "evil heart" is not taken seriously; the first syllable may be cur "dog." Liberman says the word "must have been borrowed from Gaelic (and references muigean "disagreeable person"), with variant spelling of intensive prefix ker-. Related: Curmudgeonly.

The quickest way to have first looks at etymologies is to visit
Online Etymology: Link Good site. Good word, curmudgeon. ;~)