immaterial vs insignificant

immaterial

adj
  • Having no matter or substance. 

  • So insubstantial as to be irrelevant. 

insignificant

adj
  • Without meaning; not signifying anything. 

  • Not significant; not important, inconsequential, or having no noticeable effect. 

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