Abstruse -- Ann

ab·struse  (b-strs, b-) adj. Difficult to understand; recondite. See Synonyms at ambiguous. [Latin abstrsus, past participle of abstrdere, to hide : abs-, ab-, away; see ab-1 + trdere, to push; see treud- in Indo-European roots.] ab·strusely adv. ab·struseness n.

The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

Though Ann's students may at first imagine that Calculus's logic is abstruse, Ann reveals its beauty.