birdbrain

From bird +‎ brain, implying that birds, having small brains, are unintelligent (although this is untrue for many birds).

• (UK) IPA^(key): /ˈbɜː(ɹ)d.bɹeɪn/
• (US) IPA^(key): /ˈbɚd.bɹeɪn/

• Audio (US)

  (file)

birdbrain (plural birdbrains)

1. (colloquial) Someone who is not intelligent.

   That birdbrain just drove right through three rows of traffic cones and into the bushes.

   • 1950 February 27, Time, page 38:

     Comedienne Carol Channing, 29, admitted that a grave personal problem had grown out of her playing the role of birdbrained Lorelei Lee in Broadway’s Gentlemen Prefer Blondes. People seemed to be convinced that she is a birdbrain offstage, too: “I won't say that people actually think I’m just two steps removed from outright idiocy, but they do seem to have adopted a protective attitude towards me...”