lucus a non lucendo

English

Etymology

Latin lūcus ā nōn lūcendō, literally "a grove from not shining", referring to Roman rhetorician Quintilian's assertion, in his Institutio Oratoria, that Latin lūcus (“grove”) derived from lūceō (“I shine”), because groves were dark places and did not shine.

Phrase

lucus a non lucendo

1. A form of illogical argument asserting that two things are related because they have opposite significations.
   • 1749, Henry Fielding, chapter IV, in The History of Tom Jones, A Foundling, Book VIII:

     This Sun, into which Jones was now conducted, was truly named, as lucus a non lucendo; for it was an apartment into which the sun had scarce ever looked.

   • 1873, John Camden Hotten, The Slang Dictionary:

     BUDGE, strong drink; […] Probably a corruption of BOOZE. Probably also, on the lucus a non lucendo principle, because its use made one incapable of budging.