Definition of abstruse:
multiform, bass, tangled, hermetic, heterogeneous, two-edged, equivocal, ambiguity, easy, arcane, surface, compound, entangled, nonsense, conglomerate, heavy, cryptic, thick, ill-defined, composite, deep, confused, double-edged, inscrutable, profound, mixed, mystifying, manifold, meaningless, mingled, ambiguous, cryptical, esoteric, hollow, recondite, rich.
It is the young, the light, the superficial, who are easily misled by error, and incapable of discerning its fallacy; but tell me, if it is the light, the young, the superficial, who are in the habit of reading the abstruse and subtle speculations of the philosopher.- "Pelham, Complete", Edward Bulwer-Lytton Last Updated: March 16, 2009.
Happily there is nothing else in the way of Princes of the Blood, in our little Friedrich's time; and happily what concern he had with these, or how he was related to them, will not be abstruse to us, if occasion rise.- "History Of Friedrich II. of Prussia, Vol. III. (of XXI.) Frederick The Great--The Hohenzollerns In Brandenburg--1412-1718", Thomas Carlyle.
However, if it is expected of me, like Mr. Maskelyne, to deliver an Opinion on this Point, I shall declare what I believe very sincerely, that by far the greater Part of the Commissioners are perfectly innocent of the Treatment I have met with: most of them are Commissioners by Virtue of great Employments which engage their Time and Attention: A Board so constituted is continually changing; and this being a Matter of Science which to many may seem rather abstruse, it was very naturally left to the Management of a few of those Members who stand in the most immediate Relation to Science, and whose Opinions, upon a Business of this Nature, the rest of the Board had too much Modesty to call in Question.- "Remarks on a Pamphlet Lately published by the Rev. Mr. Maskelyne, Under the Authority of the Board of Longitude", John Harrison.