pal vs pal up

pal

verb
  • Be friends with, hang around with. 

noun
  • An informal term of address, often used ironically in a hostile way. 

  • A friend, buddy, mate, cobber; someone to hang around with. 

pal up

verb
  • to become friends with. 

  • To form a small group. 

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