abstruse
英 [əb'struːs]
美[əb'strus]
	    - adj. 深奥的;难懂的
 
英英释意
- 1. difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge;
 - "the professor's lectures were so abstruse that students tended to avoid them"
 - "a deep metaphysical theory"
 - "some recondite problem in historiography"