A groat was a British silver coin of low value: four pence. For a long stretch of history it was real money in people’s pockets. Then it stopped being used, and now you meet it in history books and in old sayings. If something is not worth a groat, it is worth almost nothing. The coin was never a rich person’s piece. It was a small silver bit, and “low value” is the whole point. You will not pay with groats in a shop. Though actually, English also has another groat, spelled the same, that means a grain with the hard outer skin taken off, most often oats. Cooks still buy oat groats. That is a different word that just looks alike on the page. This one is the coin.

格羅特（英國舊時四便士銀幣）