slack off vs uncompact

slack off

verb
  • To decrease in intensity; to ease off; to diminish; to die down. 

  • To be deliberately unproductive in one's work or study. 

uncompact

verb
  • To expand from a compacted state; to uncompress computer data etc. 

adj
  • Not compact; incompact. 

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