pro·fun·di·ty 
(prə-fŭndĭ-tē, prō-)
(prə-fŭndĭ-tē, prō-)n. pl. pro·fun·di·ties
1. Great intellectual insight or understanding: profundity of thought.
2. Intensity of feeling or conviction.
3. Something profound or abstruse: the profundities of mathematics.
4. Great extent downward; great depth.
[Middle English profundite, from Old French, from Late Latin profunditās, from Latin profundus, deep; see PROFOUND.]