arduity vs task

arduity

noun
  • The state or quality of being arduous; steepness, difficulty. 

task

noun
  • A difficult or tedious undertaking. 

  • Any piece of work done. 

  • A process or execution of a program. 

  • An objective. 

  • A piece of work done as part of one’s duties. 

verb
  • To charge, as with a fault. 

  • To assign a task to, or impose a task on. 

  • To oppress with severe or excessive burdens; to tax 

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