Adjective

(en-adj)

(obsolete) Concealed or hidden out of the way; secret.

* 1612 , Thomas Shelton (translator), Miguel de Cervantes (Spanish author), The History of the Valorous and Wittie Knight-Errant Don-Quixote of the Mancha , Part 4, Chapter 15, page 500:

O who is he that could carrie newes to our olde father, that thou wert but aliue, although thou wert hidden in the most abstruse dungeons of Barbarie; for his riches, my brothers and mine would fetch thee from thence.

* 1667 , , Paradise Lost :

The eternal eye whose sight discerns abstrusest thoughts.

Difficult to comprehend or understand; recondite; obscure; esoteric.

* 1548 , Bishop John Hooper, A Declaration of the Ten Holy Comaundementes of Almygthye God , Chapter 17 Curiosity, Page 218:

...at the end of his cogitacions, fyndithe more abstruse , and doutfull obiections then at the beginning...

* 1748 , David Hume, Enquiries concerning the human understanding and concerning the principles of moral. London: Oxford University Press, 1973. § 13.

It is certain that the easy and obvious philosophy will always, with the generality of mankind, have the preference above the accurate and abstruse ;

* 1855 , , History of Latin Christianity :

Profound and abstruse topics.

Adjective

(en adjective)

Pertaining to a symbol.

* {{quote-magazine, date=2013-06-28, author=(Joris Luyendijk)

, volume=189, issue=3, page=21, magazine=(The Guardian Weekly) , title= Our banks are out of control , passage=Seeing the British establishment struggle with the financial sector is like watching an alcoholic […].  Until 2008 there was denial over what finance had become. When a series of bank failures made this impossible, there was widespread anger, leading to the public humiliation of symbolic figures.}}

Referring to something with an implicit meaning.