ambivalent vs vacillating

ambivalent

adj
  • Alternately having one opinion or feeling, and then the opposite. 

  • Simultaneously experiencing or expressing opposing or contradictory feelings, beliefs, or motivations. 

vacillating

noun
  • Vacillation. 

adj
  • Liable to vacillate. 

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