pothole vs slack

pothole

noun
  • A pit formed in the bed of a turbulent stream. 

  • A shallow pit or other edged depression in a road's surface, especially when caused by erosion by weather or traffic. 

  • A pit resulting from unauthorized excavation by treasure hunters or vandals. 

  • A shallow hole dug for the purpose of prospecting for opal or gold. 

  • A hole or recess on the top of a stove into which a pot may be placed. 

  • A vertical cave system, often found in limestone. 

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. 

verb
  • To slacken. 

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

adv
  • Slackly. 

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 pothole and slack occurred in a corpus of books? (source: Google Ngram Viewer )