Deep Thinker Meaning

(idiomatic) A person whose thoughts are profound; an intellectual.

Example: 1857, Maria Edgeworth, Vivian, ch. 9:
  Then came a disquisition on pride, with quotations and commonplaces;—then an eulogium, by his lordship, on his lordship's own knowledge of the human heart, and more especially of that "moving toyshop," the female heart; then anecdotes illustrative, comprising the gallantries of thirty years in various ranks of life, with suitable bon-mots and embellishments;—then a little French sentiment, by way of moral, with some philosophical axioms, to show that, though he had led such a gay life, he had been a deep thinker.
1923 May 19, "Mixed Motives," Time:
  THOMAS PAINE. "Oh what fun it is to be a rebel," says Mr. Bradford. Paine "was a commonplace rebel, entirely practical." Not educated, not a deep thinker.
2010 August 17, Maureen Dowd, "Opinion: Our Mosque Madness," New York Times (retrieved 18 July 2013):
  Gingrich fancies himself an intellectual, a historian, a deep thinker—the opposite number, you might say, of Sarah Palin.