slack vs weak

slack

adj
  • Lacking diligence or care; not earnest or eager. 

  • 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. 

  • Lax. 

  • Moderate in speed. 

  • Weak; not holding fast. 

adv
  • Slackly. 

noun
  • 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. 

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

  • 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. 

weak

adj
  • Unable to withstand temptation, urgency, persuasion, etc.; easily impressed, moved, or overcome; accessible; vulnerable. 

  • That does not ionize completely into anions and cations in a solution. 

  • Not having power to convince; not supported by force of reason or truth; unsustained. 

  • Lacking in vigour or expression. 

  • Unable to sustain a great weight, pressure, or strain. 

  • Definite in meaning, often used with a definite article or similar word. 

  • One of the four fundamental forces associated with nuclear decay. 

  • Dilute, lacking in taste or potency. 

  • Showing less distinct grammatical endings. 

  • Having a narrow range of logical consequences; narrowly applicable. (Often contrasted with a strong statement which implies it.) 

  • Not prevalent or effective, or not felt to be prevalent; not potent; feeble. 

  • Tending towards lower prices. 

  • Lacking in force (usually strength) or ability. 

  • Bad or uncool. 

  • Regular in inflection, lacking vowel changes and having a past tense with -d- or -t-. 

  • Resulting from, or indicating, lack of judgment, discernment, or firmness; unwise; hence, foolish. 

  • Lacking contrast. 

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