laborious vs slogging

laborious

adj
  • Mentally difficult; painstaking. 

  • Industrious. 

  • Requiring much physical effort; toilsome. 

slogging

noun
  • An act or an instance of slogging or working laboriously. 

  • A beating or thrashing. 

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