Where does “plainly” come from?

Plainly derives from Middle English -ly, Latin planum meaning "flat," Ancient Greek πλάνος, and Proto-Indo-European pleh₁-.

plainly (English): In a plain manner; simply; basically; Obviously;...

Definitions

  1. In a plain manner; simply; basically; Obviously;...

Ancestry of “plainly”, step by step

StepLanguageWordMeaning
1EnglishplainFlat, level; Simple; Obvious
2Middle Englishpleynclear; unambiguous
3Anglo-NormanpleynAlternative form of plein
4Old Frenchplayn—
5Old Frenchplainfull; plain; flat
6Latinplēnusfull; filled; complete
7Proto-Italicplēnosfull
8Proto-Indo-Europeanpl̥h₁nósfull
9Proto-Indo-Europeanpleh₁-to fill
Every word from Proto-Indo-European pleh₁- →Every word from Proto-Indo-European pl̥h₁nós →Every word from Proto-Italic plēnos →