Where does “underaid” come from?

underaid (English) comes from English aid, from Middle English aiden, from Middle French ayder, from Old French aidier, from Latin adiūtō, from Latin -tō, from Latin -tus, from Proto-Italic -tus — Derives action nouns from verb roots.

underaid (English): To aid clandestinely

Definitions

  1. To aid clandestinely

Ancestry of “underaid”, step by step

underaid traces back through two separate lines of ancestry.

via English aid

StepLanguageWordMeaning
1EnglishaidHelp; assistance; succor, relief; A helper; an...
2Middle EnglishaidenTo aid
3Middle Frenchayderto help; to aid
4Old Frenchaidierto help
5Latinadiūtōto help, serve, assist
6Latin-tōForms here
7Latin-tusForms the past participle of verbs; Forms...
8Proto-Italic-tus
9Proto-Indo-European-tusDerives action nouns from verb roots

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 -tus