elderly vs senescent

elderly

adj
  • Of an object, being old-fashioned or frail due to aging. 

  • old; having lived for relatively many years. 

noun
  • An elderly person. 

  • Older people as a whole. 

senescent

adj
  • Characteristic of old age. 

  • That ceases to divide. 

  • Growing old; decaying with the lapse of time. 

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