reflective vs serious

reflective

adj
  • Reciprocal. 

  • Involving reflection. 

  • That reveals or shows; revealing; indicative of. 

  • That reflects, or redirects back to the source. 

  • Pondering, especially thinking back on the past. 

serious

adj
  • Committed. 

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

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

  • Important; weighty; not insignificant 

adv
  • In a serious manner; seriously. 

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