dumbbell vs fathead

dumbbell

noun
  • A stupid person. 

  • A weight training implement consisting of a short bar with weight counterpoised on each end. 

fathead

noun
  • An idiot; a fool. 

  • A blobfish, Psychrolutes microporos 

  • Any of several species of fish of the genus Cubiceps 

  • A labroid food fish of California; the California sheephead. Semicossyphus pulcher. 

  • A cyprinid fish of the Mississippi valley, Pimephales promelas, the black-headed minnow. 

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