Where does “plainspokenness” come from?

plainspokenness (English) comes from English plainspoken, from English plain, from Middle English pleyn, from Anglo-Norman pleyn, from Old French playn, from Old French plain, from Latin plēnus, from Proto-Italic plēnos — to fill.

plainspokenness (English): The quality of being plainspoken

Definitions

  1. The quality of being plainspoken

Ancestry of “plainspokenness”, step by step

plainspokenness traces back through two separate lines of ancestry.

via English plainspoken

StepLanguageWordMeaning
1EnglishplainspokenSpeaking plainly or simply
2EnglishplainFlat, level; Simple; Obvious
3Middle Englishpleynclear; unambiguous
4Anglo-NormanpleynAlternative form of plein
5Old Frenchplayn
6Old Frenchplainfull; plain; flat
7Latinplēnusfull; filled; complete
8Proto-Italicplēnosfull
9Proto-Indo-Europeanpl̥h₁nósfull
10Proto-Indo-Europeanpleh₁-to fill

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 pleh₁-Every word from Proto-Indo-European pl̥h₁nósEvery word from Proto-Italic plēnos