Dear Matthew Alice: How did the expression “shit-eatinggrin” originate? We cannot imagine anyone eating shit and looking so happy! — Fran Simonet and John Moore, Faxland

No, I’m sorry but I can’t cite the first use of “shit-eating grin,” though it’s relatively recent — within the last 50 years or so. I’m more intrigued by your matched set of literal minds. If you have trouble with “shit-eating grin,” then I imagine you’ve also worried over such cliches as “Cat got your tongue?”, “You’ll pay through the nose for that!”, “Let me pick your brain,” “Get out of my hair!” or “I’m tickled to death about winning the lottery!” Metaphorical thinking is apparently not your long suit (a cliche borrowed from bridge).

One of the problems with tracing the origin of expressions that use taboo words like “shit” is that they may have been spoken for decades but were rarely written down until well into this century. We do know that the word (as a verb and noun) was spelled shite in the 14th Century, transformed to shit a couple of centuries later, with the advent of the printing press, when other English spellings started to be standardized. Word maven Stuart Flexner cites “to fall in the shit” (to get into trouble) as one of the earliest recorded expressions, from the 1870s. “Shithead,” “shit or get off the pot,” and “S.O.L" (shit out of luck) are surprisingly old; they were recorded between 1910 and 1915, which means they were probably in the spoken language long before that. But it was World War II that really turned “shit” into the friendly, all-purpose invective it is today. The word appeared in dozens of military slang terms. That, combined with a general shedding of the remnants of Victorian propriety made “shit” an okay expression to set down on paper.

As for “shit-eating grin” specifically, the expression doesn’t really mean a happy face. “Sappy” might be closer to the truth. Or “goofy,” “stupid.” It’s often used as a mild put-down to someone who’s irritating the hell out of you and having a good time doing it. Like all cliches, it’s hung around because of the vivid word picture it conjures, not for reasons of logic or grand intellectual pretensions. Besides, word experts say Americans, as a group, are suspiciously fond of anything scatological.

September 9 update

In all the T-shirt hoopla, I sidelined a postscript to the “shit-eating grin” question. Previously in “Straight from the Hip” (as they might say on TV to bring everybody up to speed), two people inquired about the origin of the term, and I confessed that no one really knew. No etymologists, at least.

But there’s always the free-lance factor to deal with. The experts without portfolio. Two such entries zapped in over the M.A. faxlines shortly after our historical treatise, Shit Happens: Six Centuries of Scatology, was published a few weeks ago. Both stories have a common theme; neither is substantiated in any research I’ve located. But that doesn’t make them incorrect. And we get the added bonus of some zoological trivia in the bargain.

First, from R.B. Smith, affiliated with the formidable UCSD astrophysics program, comes a story from his more bucolic days on a Midwest farm. “The expression does seem to have emigrated [from the farm] in a slightly evolved form. The origin was ‘Grinning like a ’possum eating shit’ (which was occasionally euphemized to ‘Grinning like a ’possum eating pumpkin seeds’). To those of us fortunate enough to have observed this teeth-together-lips-apart ‘smile’ on the face of the aforementioned marsupial munching on the aforementioned scatological delicacy, the expression conjures up a very explicit and not infrequently very apropos image.”

Fax number two, from Skip Skown of Ocean Beach, says, “I’ve been under the lifelong impression that ‘shit-eating grin’ refers to the expression that appears on a dog’s face when it’s caught gobbling up a pile of, uhhh, fecal material deposited by another animal. We’ve all seen how a dog can curl up its lips in a semblance of a grin. And we’ve also seen many dogs whose favorite snack could be found in a cat’s litter box. My theory is that it’s a sheepish grin caused by being caught in the act. Or maybe the lip motion helps clean the stuff off their teeth."

Hope the word experts will consider these contributions reliable primary source material for what is obviously a shockingly under-researched expression. Except perhaps for the digression on canine dental hygiene, these guesses sound quite rational, considering what generally passes for “common knowledge." Remember, you heard it here first.