ambulate vs knock about

ambulate

verb
  • To walk; to relocate oneself under the power of one's own legs. 

knock about

verb
  • To move or roam around aimlessly. 

  • To be mislaid in a place. 

  • To engage in a relaxing activity in a place; to hang around in. 

  • To be present at or inhabit a certain place. 

  • Often followed by with: to spend time companionably; to hang around. 

  • To live an unconventional life. 

  • To hit (someone or something) all over repeatedly; hence, to behave violently towards or mistreat (someone or something). 

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