Where does “tidyness” come from?

tidyness (English) comes from English tidy, from Middle English tidy, from English tide, from Middle English tyde, from Old English tīd, from Proto-Germanic tīdiz, from Proto-Indo-European déh₂itis, from Proto-Indo-European deh₂y- — to share, divide.

Ancestry of “tidyness”, step by step

tidyness traces back through two separate lines of ancestry.

via English tidy

StepLanguageWordMeaning
1EnglishtidyArranged neatly and in order; Not messy; neat and...
2Middle Englishtidy
3EnglishtideThe periodic change of the sea level,...
4Middle EnglishtydeA time (period), season
5Old Englishtīdtime, period, season; period, season, time;...
6Proto-Germanictīdiztime; period, interval
7Proto-Indo-Europeandéh₂itisinterval, period of time
8Proto-Indo-Europeandeh₂y-to share, divide
9Proto-Indo-Europeandeh₂-to share, divide

via English Ness

StepLanguageWordMeaning
1EnglishNessAn Ulster princess and the mother of Conchobar mac Nessa and Findchoem in the Ulster Cycle of Irish mythology. Daughter of Eochaid Sálbuide. Also the mother of Cormac Cond Longas by incest with Conchobar mac Nessa
2Middle Englishnesse
3Old Englishnæsnot, not at all; not; first/third-person singular...
4Proto-Germanicnasjąfoothill; headland; cape
5Proto-Indo-Europeannéh₂snose
Every word from Proto-Indo-European deh₂-