smooth vs tough

smooth

verb
  • To calm or palliate. 

  • To make smooth or even. 

  • To make straightforward or easy. 

  • To stroke; especially to stroke an animal's fur. 

  • To reduce to a particular shape or form by pressure; to press, to flatten. 

  • To capture important patterns in the data, while leaving out noise. 

adv
  • Smoothly. 

adj
  • Having derivatives of all finite orders at all points within the function’s domain. 

  • Flowing or uttered without check, obstruction, or hesitation; not harsh; fluent. 

  • Natural; unconstrained. 

  • Not grainy; having an even texture. 

  • Without difficulty, problems, or unexpected consequences or incidents. 

  • Involuntary and non-striated. 

  • That factors completely into small prime numbers. 

  • Having a texture that lacks friction. Not rough. 

  • Unbroken. 

  • Lacking marked aspiration. 

  • Lacking projections or indentations; not serrated. 

  • Placid, calm. 

  • Having a pleasantly rounded flavor; neither rough nor astringent. 

  • Suave; sophisticated. 

  • Bland; glib. 

noun
  • The analysis obtained through a smoothing procedure. 

  • Something that is smooth, or that goes smoothly and easily. 

  • A domestic animal having a smooth coat. 

  • A member of an anti-hippie fashion movement in 1970s Britain. 

  • A smoothing action. 

tough

verb
  • To endure. 

  • To toughen. 

adj
  • Harsh or severe. 

  • Difficult or demanding. 

  • Stubborn or persistent; capable of stubbornness or persistence. 

  • Strong and resilient; sturdy. 

  • Undergoing plastic deformation before breaking. 

  • Difficult to cut or chew. 

  • Rugged or physically hardy. 

  • Rowdy or rough. 

intj
  • Used to indicate lack of sympathy 

noun
  • A person who obtains things by force; a thug or bully. 

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