ad hoc vs off the top of head

ad hoc

adj
  • Created on the spur of the moment; impromptu. 

  • Independent of previously instated network structure, like routers or access points. 

  • For a particular purpose. 

  • Postulated solely to save a theory from being falsified, without making any new predictions. 

adv
  • On the spur of the moment. 

  • For a particular purpose. 

off the top of head

How often have the words ad hoc and off the top of head occurred in a corpus of books? (source: Google Ngram Viewer )