slack vs suck

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. 

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. 

verb
  • To slacken. 

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

adv
  • Slackly. 

suck

noun
  • A part of a river towards which strong currents converge making navigation difficult. 

  • An act of fellatio. 

  • Milk drawn from the breast. 

  • A weak, self-pitying person; a person who refuses to go along with others, especially out of spite; a crybaby or sore loser. 

  • Badness or mediocrity. 

  • An instance of drawing something into one's mouth by inhaling. 

  • An indrawing of gas or liquid caused by suction. 

  • A sycophant, especially a child. 

  • The ability to suck; suction. 

verb
  • To be inferior or objectionable: a general term of disparagement, sometimes used with at to indicate a particular area of deficiency. 

  • To perform fellatio. 

  • To work the lips and tongue on (an object) to extract moisture or nourishment; to absorb (something) in the mouth. 

  • To pull (something) in a given direction, especially without direct contact. 

  • To perform such an action; to feed from a breast or teat. 

  • To use the mouth and lips to pull in (a liquid, especially milk from the breast). 

  • To put the mouth or lips to (a breast, a mother etc.) to draw in milk. 

  • To extract, draw in (a substance) from or out of something. 

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