1. Referring to a lack of mental and physical alertness and activity: When Tom was told that he had better prepare himself for the final exam in history, his hebetudinous attitude resulted in his watching TV instead of studying and failing to pass the test the next day.
2. Relating to a lack of intelligence; dimwitted and dopey: While Jason was at the party, he noticed that some of his friends were behaving in hebetudinous ways because they had drunk too much alcohol.