acclivity vs tump

acclivity

noun
  • A slope or inclination of the earth, as the side of a hill, considered as ascending, in opposition to declivity, or descending; an upward slope; ascent. 

tump

noun
  • A mound or hillock. 

  • A tumpline. 

verb
  • To form a mass of earth or a hillock around. 

  • To fall over. 

  • To draw or drag, as a deer or other animal after it has been killed. 

  • to bump, knock (usually used with "over", possibly a combination of "tip" and "dump") 

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