incommensurate vs proportional

incommensurate

adj
  • Out of proportion (in size, degree or extent) with something else. 

proportional

adj
  • In proportion (to), proportionate. 

  • Of a typeface, having characters with natural (non-uniform) width (in contrast to monospace typefaces). 

  • At a constant ratio (to). Two magnitudes (numbers) are said to be proportional if the second varies in a direct relation arithmetically to the first. Symbol: ∝. 

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