To make someone annoyed or angry: “Connie may seem unflappable, but I know several ways to get her goat.”
A popular theory says this expression comes from a tradition in horse racing. Thought to have a calming effect on high-strung thoroughbreds, a goat was placed in the horse’s stall on the night before the race. Unscrupulous opponents would then steal the goat in an effort to upset the horse and cause it to lose the race. It’s a delightful explanation, but there’s no evidence to support it.
The exhaustive Farmer & Henley, Slang & Its Analogues, 1893, has no slang entry for goat that even remotely suggests the meaning “to anger or annoy.” But the US book Life in Sing Sing, 1904, does give “goat” as a slang term for anger. This suggests that the idiom “get one’s goat” arose fairly close to the time (1907–1908) when it first began to be seen in print.
The phrase originated in the US and the first occurrence in print was, so far as we know, in the US newspaper The Stevens Point Daily Journal, May 1909. The first English citation doesn’t occur until 1924 in the author John Galsworthy’s story White Monkey, and is obviously a recent innovation:
“That had got the chairman’s goat! – Got his goat? What expressions they used nowadays!”
Robert L. Shook in The Book of Why (1983) suggests it might have something to do with a ‘goatee’ (a beard like a goat’s). If you get someone by the goatee, it would certainly annoy them.
Another theory is that the phrase arises from an old French phrase prendre la chèvre, literally meaning “to take the goat.” But that phrases dates back to the 16th century and seems too far in the past to give rise to “get one’s goat.”
You know what? This phrase is beginning to get my goat. And anyway, it’s Sunday morning, which means it’s time for me to take a swing at the NY Times Sunday Crossword while I eat bacon and eggs.