serous vs watered-down

serous

adj
  • Containing, secreting, or resembling serum; watery; a fluid or discharge that is pale yellow and transparent, usually representing something of a benign nature. (This contrasts with the term sanguine, which means blood-tinged and usually harmful.) 

watered-down

adj
  • Diluted; containing extra water. 

  • Weakened or simplified 

How often have the words serous and watered-down occurred in a corpus of books? (source: Google Ngram Viewer )