Adjective

(er)

In shadow; darkened by shadows.

He sat in a shadowy corner.

(of character) Dark, obscure.

He was a shadowy man who rarely spoke.

* {{quote-news

, year=2011 , date=December 19 , author=Kerry Brown , title=Kim Jong-il obituary , work=The Guardian citation , page= , passage=By 1980, South Korea had overtaken its northern neighbour, and was well on its way to being one of the Asian tigers – high-performing economies, with democratic movements ultimately winning power in the 1990s. The withdrawal of most Soviet aid in 1991, with the fall of the Soviet empire, pushed North Korea further down. Kim Il-sung had held a genuine place on North Korean people's affections. His son was regarded as a shadowy playboy, with rumours circulating over the years that he imported Russian and Chinese prostitutes, and lived a life of profligacy and excess.}}

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.