abstruse
— Tillægsord
– Engelsk
~ 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"
abstrusely
— Biord
– Engelsk
~ in a manner difficult to understand; "the professor's abstrusely reasoned theories were wasted on his students"