lookout vs vanguard

lookout

noun
  • One's perspective, outlook; hence, one's responsibility. (used with a possessive pronoun or a noun in a possessive form). 

  • A session of watching for an approaching enemy, police, etc. 

  • A person on watch for approaching enemy, police, danger, etc. 

  • A vantage point with a view of the surrounding area. 

  • A joist that extends in cantilever out from the exterior wall (or wall plate) of a building, supporting the roof sheathing and providing a nailing surface for the fascia boards. 

  • An observation window. 

  • A subject for observation; a prospect or view. 

vanguard

noun
  • The person(s) at the forefront of any group or movement. 

  • The leading units at the front of an army or fleet. 

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