addlehead vs birdbrain

addlehead and birdbrain both are nouns.

Word	Noun	Adjective	Verb	Adverb
addlehead	Yes	No	No	No
birdbrain	Yes	No	No	No

As nouns, addlehead and birdbrain are synonyms defined as:

addlehead and birdbrain: a person with confused ideas; incapable of serious thought

Other synonyms of addlehead include addle-head, loon.

addlehead (noun)	birdbrain (noun)
a person with confused ideas; incapable of serious thought	a person with confused ideas; incapable of serious thought