Where does “irrationally” come from?

Irrationally comes from English irrational with the Middle English adverbial suffix -ly, from Latin irrationalis, composed of the prefix ir- (from in-, meaning "not") and -alis (meaning "of or pertaining to"), ultimately derived from Proto-Indo-European ne (negation) and ḱóm (together).

irrationally (English): In an irrational manner; without reason; in a...

Definitions

  1. In an irrational manner; without reason; in a...

Ancestry of “irrationally”, 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-