alter ego vs amigo

alter ego

noun
  • A very close and intimate friend. 

  • Somebody's alternate personality or persona; another self. 

  • A corporation used by a person to conduct personal business in an attempt to shield himself or herself from personal liability, and which a court may penetrate by "piercing the corporate veil" to impose liability on the person when they commit fraud or injustice. 

amigo

noun
  • A friend. 

  • Mexican. 

  • A native of the Philippines who was friendly toward the Spanish. 

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