hold down vs self-control

hold down

verb
  • To restrain; to check. 

  • To continue, to hold and to manage well. 

self-control

verb
  • To control oneself or itself. 

noun
  • The ability to control one's desires and impulses; willpower. 

How often have the words hold down and self-control occurred in a corpus of books? (source: Google Ngram Viewer )