legal vs underground

legal

noun
  • Paper in sheets 8½ in × 14 in (215.9 mm × 355.6 mm). 

  • The legal department of a company. 

  • Somebody who immigrated lawfully. 

  • A spy who is attached to, and ostensibly employed by, an embassy, military outpost, etc. 

adj
  • Relating to the law or to lawyers. 

  • Having its basis in the law. 

  • Being allowed or prescribed by law. 

  • Above the age of consent or the legal drinking age. 

  • Following the rules or syntax of a system, such as a game or a programming language. 

  • (of paper or document layouts) Measuring 8½ in × 14 in (215.9 mm × 355.6 mm) (also legal-size). 

underground

adv
  • Below the ground. 

  • Secretly. 

adj
  • Hidden, furtive, secretive. 

  • Below the ground; below the surface of the Earth. 

  • Outside the mainstream, especially unofficial and hidden from the authorities. 

noun
  • A movement or organisation of people who resist artistic convention. 

  • A movement or organisation of people who resist political convention. 

  • Regions beneath the surface of the earth, both natural (eg. caves) and man-made (eg. mines). 

  • Synonym of subway: a railway that is under the ground. 

verb
  • To route electricity distribution cables underground. 

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