loiter vs plod

loiter

noun
  • A standing or strolling about without any aim or purpose. 

verb
  • To remain at a certain place instead of moving on. 

  • To stand about without any aim or purpose; to stand about idly. 

  • For an aircraft to remain in the air near a target. 

plod

noun
  • A slow or labored walk or other motion or activity. 

  • the police, police officers 

  • a police officer, especially a low-ranking one. 

verb
  • To walk or move slowly and heavily or laboriously (+ on, through, over). 

  • To toil; to drudge; especially, to study laboriously and patiently. 

  • To trudge over or through. 

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