From Middle English magot, magat, maked, probably a metathetic alteration of maddock, maðek (“worm", "maggot”), originally a diminutive form of a base represented by Old English maþa (Scots mathe), from Proto-West Germanic *maþō, from Proto-Germanic *maþô, from the Proto-Indo-European root *mat, which was used in insect names, equivalent to made + -ock. Near-cognates include Dutch made, German Made and Swedish mask, Icelandic maðkur (“worm, grub, maggot”). The use of maggot to mean a fanciful or whimsical thing derives from the folk belief that a whimsical or crotchety person had maggots in their brain.
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A soft, legless larva of a fly or other dipteran insect, that often eats decomposing organic matter.
Are you not mad, my friend? What time o' th' moon is't? / Have not you maggots in your brain?1620, John Fletcher, Women Pleased, III.iv:
‘I am ashamed of him! how can he think of humouring you in such maggots!’1778, Frances Burney, Journals & Letters, Penguin, published 2001, page 100:
2 more examples
[…] If you draw, Sir, there's one prospect up the river, by the mills—upon my conscience—but you don't draw?' No answer. 'A little, Sir, maybe? Just for a maggot, I'll wager—like my good lady, Mrs. Toole.'1863, Sheridan Le Fanu, The House by the Churchyard:
Scotland Yard have two maggots which crop up whenever anything happens to a young woman. Either it’s White Slavery or Dope Dens—sometimes both.1927, Dorothy Sayers, Unnatural Death:
(We) We are the new diabolic (We) We are the bitter bucolic If I have to give my life, you can have it (We) We are the pulse of the maggots2004, “Pulse of the Maggots”, performed by Slipknot:
From Middle English magot, magat, maked, probably a metathetic alteration of maddock, maðek (“worm", "maggot”), originally a diminutive form of a base represented by Old English maþa (Scots mathe), from Proto-West Germanic *maþō, from Proto-Germanic *maþô, from the Proto-Indo-European root *mat, which was used in insect names, equivalent to made + -ock. Near-cognates include Dutch made, German Made and Swedish mask, Icelandic maðkur (“worm, grub, maggot”). The use of maggot to mean a fanciful or whimsical thing derives from the folk belief that a whimsical or crotchety person had maggots in their brain.
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To rid (an animal) of maggots.
In the summer I had to get the sheep penned twice a day to maggot them and I needed a good dog.1950, Frederick Daniel Smith, Barbara Wilcox, Sold for Two Farthings, page 82: