Sadness
来自Big Physics
Old English sæd ‘sated, weary’, also ‘weighty, dense’, of Germanic origin; related to Dutch zat and German satt, from an Indo-European root shared by Latin satis ‘enough’. The original meaning was replaced in Middle English by the senses ‘steadfast, firm’ and ‘serious, sober’, and later ‘sorrowful’.
wiktionary
From Middle English sadnesse, equivalent to sad + -ness.
etymonline
sadness (n.)
early 14c., "seriousness," from sad + -ness. Meaning "sorrowfulness" is c. 1500, perhaps c. 1400.
