The adjective obtuse means dull, imperceptive, or slow to understand. The word obtuse is usually applied to people and their behavior. (In geometry, obtuse refers to an angle of between 90 and 180 degrees.)
- The schoolchildren were puzzled by the poet's lengthy and abstruse lecture on symbolism.
- The woman spoke simply, using words that even the most obtuse politician could understand.
(a) Only an _____ teacher would persist in using techniques that were ineffective for stimulating learning.
(b) The author conveys her points clearly and directly without resorting to jargon or _____ explanations.