extremeness of degree;
"the profoundness of his ignorance"
wisdom that is recondite and abstruse and profound;
"the anthropologist was impressed by the reconditeness of the native proverbs"
the intellectual ability to penetrate deeply into ideas
the quality of being physically deep;
"the profundity of the mine was almost a mile"
intellectual depth; penetrating knowledge; keen insight; etc;
"the depth of my feeling"
"the profoundness of the silence"