hebetudinous

adj

1. Displaying mental lethargy or dullness.

   “His hebetudinous lack of curiosity enraged the instructor.”

   “Exclusive dedication to necessitous chores without interludes of hedonistic diversion renders Jack a hebetudinous fellow.”

   “comebacks concocted, not said out loud, / would have been incomprehensible to the hebetudinous.”