Where does “thineself” come from?

thineself (English) comes from English thine, from Middle English þyn, from Old English þīn, from Proto-Germanic *þīn, from Proto-Germanic þīnaz, from Proto-Indo-European téynos, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “thineself”, step by step

thineself traces back through two separate lines of ancestry.

via English thine

StepLanguageWordMeaning
1EnglishthineSingular second person prevocalic possessive...
2Middle EnglishþynAlternative form of þin
3Old Englishþīnyour (singular), thine, thy
4Proto-Germanic*þīn
5Proto-Germanicþīnazyour, yours (thy, thine); 2nd person singular possessive
6Proto-Indo-Europeantéynosthy; thine
7Proto-Indo-Europeantúh₂you, thou

via English Self

StepLanguageWordMeaning
1EnglishSelfHimself, herself, itself, themself, themselves; that specific (person mentioned)
2Middle EnglishsalveAlternative form of sauf
3Old Englishsealfsalve
4Proto-West Germanicsalbusalve, ointment
5Proto-Germanicsalbōsalve, ointment
6Proto-Indo-Europeansolp-éh₂
7Proto-Indo-Europeanselp-fat, oil
Every word from Proto-Indo-European túh₂Every word from Proto-Indo-European téynosEvery word from Proto-Germanic þīnaz