rocking vs whitecap

rocking

noun
  • The motion of something that rocks. 

  • The abrading of a copper plate with a rocker, preparatory to mezzotinting. 

  • The motion by which the design on a steel mill is transferred to a copper cylinder. 

adj
  • Excellent; great. 

  • Shaking, swaying or moving back and forth. 

whitecap

noun
  • A wave having a white crest; a breaker 

  • Any of several birds having a white patch on the head 

  • A member of a self-appointed vigilante committee that carried out lynchings. Some early ones wore white hoods or masks. 

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