hidden or hidden out-of-the-way
- tough to penetrate; incomprehensible to at least one of ordinary understanding or knowledge
- Concealed or concealed taken care of.
- Remote from apprehension; hard to be comprehended or recognized; recondite; as, abstruse understanding.
a thing that is more difficult to understand for those with just basic knowledge on the subject.
1590s, from center French abstrus (16c.) or straight from Latin abstrusus "hidden, concealed, secret," past participle of abstrudere "hide," actually "to thrust away," from ab- "away" (see ab-) + trudere "to push, push" (see extrusion). Relevant: Abstrusely; abstruseness.
(a.) hidden or concealed out of the way.
- (a.) Remote from apprehension; hard to be understood or comprehended; recondite; since, abstruse understanding.
It would have been a hopeless task to make Helen comprehend the more abstruse meanings of the word MYSTERY, but she understood readily that it signified something hidden or concealed, and when she makes greater progress she will grasp its more abstruse meaning as easily as she now does the simpler signification.