Where does “no-brainer” come from?

no-brainer (English) comes from English Nō, from Middle English no, from Old English nā, from Old English ne, from Old English ealles, from Old English -es, from Proto-Germanic -as, from Proto-Indo-European -ēs — Creates action nouns or result nouns from verbs;...

no-brainer (English): An easy or obvious conclusion, decision, solution; something requiring little or no thought

Definitions

  1. An easy or obvious conclusion, decision, solution; something requiring little or no thought

Ancestry of “no-brainer”, step by step

no-brainer traces back through two separate lines of ancestry.

via English

StepLanguageWordMeaning
1English
2Middle Englishnono
3Old Englishno
4Old Englishnenot; or, and not; "ne... ne..." is used to mean "...
5Old Englisheallescompletely, wholly, entirely; totally,...
6Old English-espossessive marker, indicating that an object...
7Proto-Germanic-asused in formation of adverbs
8Proto-Indo-European-ēsPrimarily forms adjectival bahuvrīhi compounds
9Proto-Indo-European-ess
10Proto-Indo-European-osCreates action nouns or result nouns from verbs;...

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 -os
no-brainer — Etymology, Origin & Word History | Etymology Explorer