Where does “fleabrain” come from?

fleabrain (English) comes from English flea, from Middle English fle, from Old English flēa, from Proto-West Germanic flauh, from Proto-Germanic flauhaz, from Proto-Indo-European plówkos, from Proto-Indo-European plúsis — flea.

fleabrain (English): A stupid or foolish person

Definitions

  1. A stupid or foolish person

Ancestry of “fleabrain”, step by step

fleabrain traces back through two separate lines of ancestry.

via English flea

StepLanguageWordMeaning
1EnglishfleaA small, wingless, parasitic insect of the order...
2Middle Englishfleflea
3Old Englishflēa
4Proto-West Germanicflauhflea
5Proto-Germanicflauhazflea
6Proto-Indo-Europeanplówkos
7Proto-Indo-Europeanplúsisflea

via English brain

StepLanguageWordMeaning
1EnglishbrainThe control center of the central nervous system...
2Middle EnglishbraynThe brain or cerebrum; the organ of thought;...
3Old Englishbræġnbrain
4Proto-West Germanic*bragnbrain
5Proto-Germanicbragnąbrain
6Proto-Indo-Europeanmregʰnomskull, brain
7Proto-Indo-Europeanmen-to think, mind; spiritual activity; to stay,...
Every word from Proto-Indo-European plúsis