allowable vs legal

allowable

adj
  • Permissible; tolerable; legitimate. 

  • Appropriate; satisfactory; acceptable. 

  • Intellectually admissible; valid; probable. 

  • Able to be added or deducted in consideration of something. 

noun
  • permitted amount or activity. 

legal

adj
  • Being allowed or prescribed by law. 

  • Relating to the law or to lawyers. 

  • Having its basis in the 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). 

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. 

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