deep vs principal

deep

adj
  • Significant, not superficial, in extent. 

  • In a (specified) number of rows or layers. 

  • Positioned or reaching far, especially down through something or into something. 

  • Voluminous. 

  • Far in extent in another (non-downwards, but generally also non-upwards) direction away from a point of reference. 

  • Low in pitch. 

  • Far from the center of the playing area, near to the boundary of the playing area, either in absolute terms or relative to a point of reference. 

  • Distant in the past, ancient. 

  • Muddy; boggy; sandy; said of roads. 

  • Extending far down from the top, or surface, to the bottom, literally or figuratively. 

  • Penetrating a long way, especially a long way forward. 

  • Hard to penetrate or comprehend; profound; intricate; obscure. 

  • Positioned back, or downfield, towards one's own goal, or towards or behind one's baseline or similar reference point. 

  • Thick. 

  • Profound, having great meaning or import, but possibly obscure or not obvious. 

  • Extending to a level or length equivalent to the stated thing. 

  • Highly saturated; rich. 

  • Sound, heavy (describing a state of sleep from which one is not easily awoken). 

  • Of penetrating or far-reaching intellect; not superficial; thoroughly skilled; sagacious; cunning. 

adv
  • In a profound, not superficial, manner. 

  • In large volume. 

  • Back towards one's own goal, baseline, or similar. 

  • Far, especially far down through something or into something, physically or figuratively. 

noun
  • A deep hole or pit, a water well; an abyss. 

  • A deep shade of colour. 

  • A silent time; quiet isolation. 

  • The deep part of a lake, sea, etc. 

  • The profound part of a problem. 

  • A fielding position near the boundary. 

  • The sea, the ocean. 

principal

adj
  • Primary; most important; first level in importance. 

  • Chosen or assumed among a branch of possible values of a multi-valued function so that the function is single-valued. 

noun
  • The chief administrator of a school. 

  • A diapason, a type of organ stop on a pipe organ. 

  • The construction that gives shape and strength to a roof, generally a truss of timber or iron; or, loosely, the most important member of a piece of framing. 

  • A dancer at the highest rank within a professional dance company, particularly a ballet company. 

  • The primary participant in a crime. 

  • The first two long feathers of a hawk's wing. 

  • A security principal. 

  • A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a negotiorum gestio acts. 

  • The chief executive and chief academic officer of a university or college. 

  • The money originally invested or loaned, on which basis interest and returns are calculated. 

  • A partner or owner of a business. 

  • One of the turrets or pinnacles of waxwork and tapers with which the posts and centre of a funeral hearse were formerly crowned 

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