That was the only Latin my dad knew! - setters who trawl `Chamber`s` searching for obscure references, which hardly anyone uses, aren`t really that clever.
@tyke: I'm familiar with another version of that mock Latin expression - illegitimus non tatum carborundum - and taught it to my mother, decades ago. She delighted in saying it to co-workers when she felt they should indeed 'not let the b*stards grind you down'.
I confess! I'm a trawler. I'm not deliberately looking for obscure words, but sometimes I find a word or abbreviation which suits the clue, and happens to be obscure.