abstruse (adjective): difficult to comprehend
The directions to the game were abstruse, so we decided to play something else.
More than many other abstruse areas of higher mathematics, chaos theory has captured the public imagination.— Martin Weil, BostonGlobe.com, "Mitchell Feigenbaum, an architect of chaos theory, dies at 74," 14 July 2019
synonyms: recondite, esoteric, arcane
antonyms: shallow, superficial
Origin: borrowed from Latin abstrūsus "concealed, recondite," from past participle of abstrūdere "to conceal," from abs- (variant of ab- AB- before c- and t-) + trūdere "to push, thrust"
First known usage: 1549