Where does “plain and simple” come from?

plain and simple (English) comes 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, from Proto-Indo-European pl̥h₁nós — to fill.

plain and simple (English): Clearly, without any doubt or complexity

Definitions

  1. Clearly, without any doubt or complexity

Ancestry of “plain and simple”, step by step

plain and simple traces back through 3 separate lines of ancestry.

via English plain

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

via English simple

StepLanguageWordMeaning
1EnglishsimpleUncomplicated; taken by itself, with nothing...
2Middle Englishsymplevirtuous, godly, without sin; simple, spartan,...
3Old Frenchsimpleinnocent; mere; simple; honest; without pretense
4Latinsimplexsingle; simple, plain, uncompounded; pure,...
5Latin-plex-fold
6Latinplicōto fold, bend or flex; to roll up
7Proto-Indo-Europeanpleḱ-to fold, plait, weave
8Proto-Indo-Europeanpel-to cover, to wrap; skin, hide, cloth; to fold

via English AND

StepLanguageWordMeaning
1EnglishANDAlternative form of ∧, the conjunction operator;...
2Middle Englishandand, and then; however, yet, but, though. while;...
3Old Englishandand; even; also
4Proto-Germanicandiin addition, furthermore, and
5Proto-Indo-Europeanh₂éntiopposite; near; in front
6Proto-Indo-Europeanh₂éntsforehead; front
7Proto-Indo-Europeanh₂ent-face; forehead; front
8Proto-Indo-Europeanh₂en-on, onto
Every word from Proto-Indo-European pleh₁-Every word from Proto-Indo-European pl̥h₁nósEvery word from Proto-Italic plēnos