complexity vs restraint

complexity

noun
  • That which is and renders complex; intricacy; complication. 

  • The state of being complex; intricacy; entanglement. 

restraint

noun
  • something that restrains, ties, fastens or secures 

  • control or caution; reserve 

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