sad

Etymology 1

From Middle English sad, from Old English sæd (“sated, full”), from Proto-Germanic *sadaz (“sated, satisfied”), from Proto-Indo-European *seh₂- (“to satiate, satisfy”).

adj

1. (heading) Emotionally negative.
   1. Feeling sorrow; sorrowful, mournful.
      She gets sad when he's away.
   2. Appearing sorrowful.
      The puppy had a sad little face.
      We need a sad man. Give us a sad man.” Tomo gave the look of a sad man, then followed with the body of a sad man. “That's it, more of that. can you manufacture a mole right here? Yes, a very ugly mole. Right here, on the chin.[…] 2010-02, Eric Rentschler, Itoh's Ghost, iUniverse, →OCLC, page 54
   3. Causing sorrow; lamentable.
      It's a sad fact that most rapes go unreported.
      The Great Gaels of Ireland are the men that God made mad, / For all their wars are merry and all their songs are sad. 1911, G. K. Chesterton, The Ballad of the White Horse
   4. Poor in quality, bad; shameful, deplorable; later, regrettable, poor.
      That's the saddest-looking pickup truck I've ever seen.
   5. Of colours: dark, deep; later, sombre, dull.
      sad-coloured clothes 1679, Izaak Walton, The Life of Bishop Robert Sanderson
2. (obsolete) Sated, having had one's fill; satisfied, weary.
3. (obsolete) Steadfast, valiant.
4. (obsolete) Dignified, serious, grave.
   Therfore it nedeth that better prouysion. 1509, Sebastian Brant, translated by Alexander Barclay, The Ship of Fools,
5. (obsolete) Naughty; troublesome; wicked.
   Mr. Santon laughed, and merely said,—"Oh, you cruel beauty!" returning to his paper again; but, seated in the bay-window was one, who could not thus lightly look upon the conduct of the coquettish Winnie, for it was evident she was a sad coquette. 1859, Ferna Vale, Natalie; or, A Gem Among the Sea-Weeds
6. (slang) Unfashionable; socially inadequate or undesirable.
   I can't believe you use drugs; you're so sad!
7. (dialect) Soggy (to refer to pastries).
8. (obsolete) Heavy; weighty; ponderous; close; hard.
   sad bread

verb

1. (transitive, archaic) To make melancholy; to sadden or grieve (someone).
   16??, John Webster, Appius and Virginia My father's wondrous pensive, and withal / With a suppress'd rage left his house displeas'd, / And so in post is hurried to the camp: / It sads me much; to expel which melancholy, / I have sent for company.

Etymology 2

noun

1. Alternative form of saad (“Arabic letter”)