burrow vs undersee

burrow

verb
  • (with into) to investigate thoroughly 

  • (with adverbial of direction) to move underneath or press up against in search of safety or comfort 

  • to dig a tunnel or hole 

noun
  • A tunnel or hole, often as dug by a small creature. 

  • A heap or heaps of rubbish or refuse. 

undersee

verb
  • To look intently into; examine; inspect. 

  • To see or look under or below; see below the surface of. 

  • To neglect; fail to see properly or adequately; turn a blind eye to; ignore. 

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