softheadedness

/ˌsɔftˈhɛdɪdnəs/
noun
  1. The quality or state of being foolish, silly, or lacking good judgment.
    • The teacher was frustrated by the softheadedness of students who didn't study for the exam.
    • His softheadedness led him to invest all his savings in a fake business scheme.
    • Softheadedness in politics can result in policies that harm the economy.
Antonyms