featherbrain

/ˈfɛðərˌbreɪn/
noun
  1. A silly or forgetful person; someone who is not very smart or who acts without thinking.
    • Don't be such a featherbrain—you left your keys in the door again!
    • She called herself a featherbrain after mixing up the meeting times.
    • He's a bit of a featherbrain, always forgetting appointments.
Antonyms
What does "featherbrain" mean? | whatsthatwordmean | whatsthatwordmean