It may seem 'abstruse,' but consider using it instead of 'obtuse'
I saw a common tangling of "obtuse" and "abstruse" tonight in a Chronicle of Higher Ed article in which Michael Bugeja bemoans how faculty rubber-stamp new degree programs. It's worth reading, by the way, but for this moment, the focus is on this passage:
Promoted by the corporate world, RCM essentially operates on one concept: Reward revenue-generating activities, such as student credit hours. That is touted as "transparency," a welcome change from obtuse budget formulas by central administration.
While Merriam-Webster shows this use of obtuse (difficult to comprehend) as a secondary usage (derived from increasingly common usage), the better word is abstruse. It clearly means difficult to comprehend, with no other definition. (Neither American Heritage 4 nor Webster's New World have adopted the more liberal usage.)
So use obtuse if you must, but for clarity, consider abstruse.