Where does “உண்ணீர்” come from?

உண்ணீர் (Tamil) comes from Tamil நீர், from Old Tamil 𑀦𑀻𑀭𑁰, from Proto-Dravidian nīr — you; water.

Ancestry of “உண்ணீர்”, step by step

உண்ணீர் traces back through two separate lines of ancestry.

via Tamil நீர்

StepLanguageWordMeaning
1Tamilநீர்water
2Old Tamil𑀦𑀻𑀭𑁰y'all
3Proto-Dravidiannīryou; water

via Tamil உண்

StepLanguageWordMeaning
1Tamilஉண்to eat
2Proto-Dravidian*uHṇto eat, drink
Every word from Proto-Dravidian nīr →Every word from Old Tamil 𑀦𑀻𑀭𑁰 →Every word from Tamil நீர் →