Where does “underproof” come from?

underproof (English) comes from English proof, from Middle English proof, from Old French prove, from Latin proba, from Latin probāre, from Latin probō, from Latin Probus, from Proto-Indo-European pro-bhwo- — passed , crossed.

underproof (English): Having a lower alcohol content than proof spirit;...

Definitions

  1. Having a lower alcohol content than proof spirit;...

Ancestry of “underproof”, step by step

underproof traces back through two separate lines of ancestry.

via English proof

StepLanguageWordMeaning
1EnglishproofAn effort, process, or operation designed to...
2Middle Englishproof
3Old Frenchprove
4Latinprobatest, trial; proof, evidence
5Latinprobāre
6Latinprobōto approve, permit, commend
7LatinProbusgood, serviceable, excellent, superior, able
8Proto-Indo-Europeanpro-bhwo-being in front, prominent
9Proto-Indo-Europeanpro-toward, forward
10Proto-Indo-Europeanpor-to give birth; forward, through; going, passage
11Proto-Indo-Europeanper-before, in front; first; to go through
12Proto-Indo-Europeanpr̥tóspassed , crossed

via English under

StepLanguageWordMeaning
1EnglishunderIn or at a lower level than; As a subject of;...
2Middle Englishunderunder
3Old Englishunderunder, beneath
4Proto-Germanicunderamong, between; under, beneath; under
5Proto-Indo-Europeanh₁entérbetween
6Proto-Indo-Europeanh₁enin; in, inside
Every word from Proto-Indo-European pr̥tósEvery word from Proto-Indo-European per-Every word from Proto-Indo-European por-