What is the Latin word for irrelevant?

The usual Latin words for “irrelevant” are aliēnus, referō. The right choice depends on the sense; see the distinctions below.

English → Latin

“irrelevant” in Latin

aliēnusOf that which belongs to another person, place, or object—of another, alien, foreign; unfriendly, inimical, hostile, sus referōto bear, bring, drive, or carry back, off, or away; to give back, give up, return, restore, pay back, repay, render, pay

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

irrelevant

aliēnus (foreign to; in this sense the dative is best: illi causae, Cic.; quibus omnibus, Quint.). Very irrelevant, maxime alienus: I did not consider it irrelevant to, etc., haud ab re duxi (referre, etc., Cic.).

Quick answer

What is the Latin word for irrelevant?: The usual Latin words for “irrelevant” are aliēnus, referō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.