bog vs slack

bog

noun
  • A little elevated spot or clump of earth, roots, and grass, in a marsh or swamp. 

  • The acidic soil of such areas, principally composed of peat; marshland, swampland. 

  • Confusion, difficulty, or any other thing or place that impedes progress in the manner of such areas. 

  • A place to defecate: originally specifically a latrine or outhouse but now used for any toilet. 

  • An act or instance of defecation. 

  • An area of decayed vegetation (particularly sphagnum moss) which forms a wet spongy ground too soft for walking; a marsh or swamp. 

verb
  • To make a mess of something. 

  • To be prevented or impeded from making progress, to become stuck. 

  • To sink or submerge someone or something into bogland. 

  • To prevent or slow someone or something from making progress. 

  • To defecate, to void one's bowels. 

  • To cover or spray with excrement. 

  • To sink and stick in bogland. 

  • To go away. 

slack

noun
  • A tidal marsh or shallow that periodically fills and drains. 

  • Unconditional listening attention given by client to patient. 

  • A temporary speed restriction where track maintenance or engineering work is being carried out at a particular place. 

  • The part of anything that hangs loose, having no strain upon it. 

  • Small coal; coal dust. 

  • A valley, or small, shallow dell. 

adv
  • Slackly. 

verb
  • To slacken. 

  • To lose cohesion or solidity by a chemical combination with water; to slake. 

adj
  • Moderately warm. 

  • Vulgar; sexually explicit, especially in dancehall music. 

  • Not active or busy, successful, or violent. 

  • Excess; surplus to requirements. 

  • Lax; not tense; not firmly extended. 

  • Lacking diligence or care; not earnest or eager. 

  • Lax. 

  • Moderate in speed. 

  • Weak; not holding fast. 

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