imperatorial vs incumbent

imperatorial

adj
  • Relating to the title or office of imperator. 

  • Commanding; authoritative. 

incumbent

adj
  • Being the current holder of an office or a title. 

  • Lying; resting; reclining; recumbent. 

  • Imposed on someone as an obligation, especially due to one's office. 

  • Resting on something else; in botany, said of anthers when lying on the inner side of the filament, or of cotyledons when the radicle lies against the back of one of them 

  • Prevalent, prevailing, predominant. 

  • Bent downwards so that the ends touch, or rest on, something else. 

noun
  • The current holder of an office, such as ecclesiastical benefice or an elected office. 

  • A holder of a position as supplier to a market or market segment that allows the holder to earn above-normal profits. 

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