Where does “pissbrain” come from?

pissbrain (English) comes from English brain, from Middle English brayn, from Old English bræġn, from Proto-West Germanic *bragn, from Proto-Germanic bragną, from Proto-Indo-European mregʰnom, from Proto-Indo-European men- — to think, mind; spiritual activity; to stay,...

Ancestry of “pissbrain”, step by step

pissbrain traces back through two separate lines of ancestry.

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,...

via English piss

StepLanguageWordMeaning
1EnglishpissUrine; An instance of pissing; Alcoholic...
2Middle Englishpissepiss, urine; Alternative form of pissen
3Middle EnglishpissenTo piss; to deliver urine from the genitals; To...
4Old Frenchpissierto piss; to excrete urine
5Vulgar Latinpissiarepresent active infinitive of *pīssiō
6LatinpissioI piss
Every word from Proto-Indo-European men-