helmet vs mug

helmet

noun
  • A contemptible or stupid person. 

  • The hood-shaped upper sepal or petal of some flowers, as of the monkshood or the snapdragon. 

  • A naked shield or protuberance on the top or fore part of the head of a bird. 

  • The feature above a shield on a coat of arms. 

  • The glans penis. 

  • A hard, protective head covering, typically part of armour. 

  • The upper part of a chemist's retort. 

verb
  • To cover with, or as if with, a helmet. 

mug

noun
  • A stupid or contemptible person. 

  • A gullible or easily-cheated person. 

  • The face. 

  • A criminal. 

  • A large cup for beverages, usually having a handle and used without a saucer. 

  • Motherfucker (usually in similes, e.g. "like a mug" or "as a mug") 

adj
  • Uninteresting or unpleasant. 

verb
  • To assault for the purpose of robbery. 

  • To photograph for identification; to take a mug shot. 

  • To exaggerate a facial expression for communicative emphasis; to make a face, to pose, as for photographs or in a performance, in an exaggerated or affected manner. 

  • To learn or review a subject as much as possible in a short time; cram. 

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