abstruse
ab-STROOSadjMeaning very hard to understand
Memory hook AB-STRUSE: pushed AWAY out of reach. Professor Edwin fills the board with symbols so tangled that every student’s head spins; the meaning is pushed far out of reach. His lecture is abstruse.
The professor’s abstruse lecture lost half the class in the first ten minutes.
In context The instruction manual was abstruse, full of technical terms and tangled diagrams that even the engineer struggled to follow.
Similar obscure, difficult, impenetrable, complex
Opposite clear, simple, plain
From Latin abstrusus, “hidden,” from abstrudere (to push away, to conceal): abs- (away) + trudere (to push).