overtask vs submerge

overtask

verb
  • To task too heavily; to give someone or something too many tasks; to overburden. 

submerge

verb
  • To engulf or overwhelm. 

  • To sink out of sight. 

  • To put into a liquid; to immerse; to plunge into and keep in. 

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