Where does “underimmunise” come from?

underimmunise (English) comes from English under, from Middle English under, from Old English under, from Proto-Germanic under, from Proto-Indo-European h₁entér, from Proto-Indo-European h₁en — in; in, inside.

Ancestry of “underimmunise”, step by step

underimmunise traces back through two separate lines of ancestry.

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

via English immunise

StepLanguageWordMeaning
1Englishimmunise—
2Frenchimmuniserto immunize/immunise
Every word from Proto-Indo-European h₁en →Every word from Proto-Indo-European h₁entér →Every word from Proto-Germanic under →