back off vs invaginate

back off

verb
  • To move backwards away from something. 

  • To become less aggressive, particularly when one had appeared committed to act. 

  • To lower the setting of. 

  • You need to back off, or the situation could turn ugly. 

  • Used other than figuratively or idiomatically: see back, off. 

invaginate

verb
  • To turn or fold inwardly. 

  • To fold inward to create a hollow space where none had existed, as with a gastrula forming from a blastula. 

  • To fold up or enclose into a sheath-like or pouch-like structure, either naturally or as part of a surgical procedure. 

adj
  • Having one portion of a hollow organ drawn back within another portion. 

  • sheathed 

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