duck out vs naff off

duck out

verb
  • To move or act so as to achieve avoidance, escape, or evasion. 

  • To depart quickly or exit abruptly by way of, especially in a manner which does not attract notice and before a meeting, event, etc. has concluded. 

  • To depart quickly or exit abruptly, especially in a manner which does not attract notice and before a meeting, event, etc. has concluded. 

naff off

verb
  • A mild version of fuck off 

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