Merriam-Webster Collegiate Dictionary - profound

 I. adjective  Etymology: Middle English, from Anglo-French parfunt, profond deep, from Latin profundus, from pro- before + fundus bottom — more at pro-, bottom  Date: 14th century  1.  a. having intellectual depth and insight  b. difficult to fathom or understand  2.  a. extending far below the surface  b. coming from, reaching to, or situated at a depth ; deep-seated a ~ sigh  3.  a. characterized by intensity of feeling or quality  b. all encompassing ; complete ~ sleep ~ deafness  • ~ly adverb  • ~ness noun  II. noun  Date: 1621 archaic something that is very deep; specifically the depths of the sea