dither (v.)youdaoicibaDictYouDict[dither 词源字典]
1640s, "to quake, tremble," phonetic variant of Middle English didderen (late 14c.), which is of uncertain origin. The sense of "vacillate, be anxious" is from 1819. Related: Dithered; dithering.[dither etymology, dither origin, 英语词源]