hump vs knap

hump

verb
  • To bend something into a hump. 

  • To carry (something), especially with some exertion. 

  • To shunt wagons / freight cars over the hump in a hump yard. 

  • To dry-hump. 

  • To have sex (with). 

noun
  • A mound of earth. 

  • An act of sexual intercourse. 

  • A bad mood. 

  • A speed bump or speed hump. 

  • A wave that forms in front of an operating hovercraft and impedes progress at low speeds. 

  • A rounded fleshy mass, such as on a camel or zebu. 

  • A painfully boorish person. 

  • A deformity in humans caused by abnormal curvature of the upper spine. 

knap

verb
  • To make a sound of snapping. 

  • To rap or strike sharply. 

  • To shape a brittle material having conchoidal fracture, usually a mineral (flint, obsidian, chert etc.), by breaking away flakes, often forming a sharp edge or point. 

noun
  • A protuberance; a swelling; a knob. 

  • A small hill 

  • A sharp blow or slap. 

  • The crest of a hill 

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