Where does “irrationality” come from?

Irrationality derives from English irrational plus the suffix -ity, from French -ité, Latin -itas, ultimately from Proto-Indo-European ne and h₁én.

irrationality (English): The quality or state of being irrational; want of...

Definitions

  1. The quality or state of being irrational; want of...

Ancestry of “irrationality”, step by step

StepLanguageWordMeaning
1EnglishirrationalNot rational; unfounded or nonsensical; Of a real...
2Latinirratiōnālisirrational
3Latinrationalisaccounts; rational, reasonable, of or possessing...
4Latinratiōreason, reasoning, explanation, ground, motive, rationality, rationale, purpose
5Latin-tiōtion, -ation, -ing
6Latindissertātiō(spoken) dissertation, discourse, disquisition
7Latindissertusarranged, disposed; explained
8Latindissereresecond-person singular future passive indicative...
9Latindis-asunder, apart, in two; reversal, removal;...
10Latincalceusshoe
11Latincalxlimestone; chalk; the finish line
12Ancient Greekχάλιξsmall stone, pebble; gravel, rubble
Every word from Ancient Greek χάλιξEvery word from Latin -tiōEvery word from Latin dis-