brooding vs serious

brooding

adj
  • Deeply or seriously thoughtful. 

  • Broody; incubating eggs by sitting on them. 

noun
  • A spell of brooding; the time when someone broods. 

serious

adj
  • Really intending what is said (or planned, etc); in earnest; not jocular or deceiving 

  • Committed. 

  • Without humor or expression of happiness; grave in manner or disposition 

  • Important; weighty; not insignificant 

adv
  • In a serious manner; seriously. 

How often have the words brooding and serious occurred in a corpus of books? (source: Google Ngram Viewer )