floccinaucinihilipilification

The story

1. Proto-Indo-European*bʰlok-
2. Latinfloccus
3. Latinnaucum
4. Proto-Indo-European*né
5. Old Latinne
6. Latinne-
7. Latinhīlum
8. Latinnihilum
9. Proto-Indo-European*pil-?
10. Latinpilus
11. English todayfloccinaucinihilipilification

From Latin floccus (“a wisp”) + naucum (“a trifle”) + nihilum (“nothing”) + pilus (“a hair”) + -fication. A pseudo-Latinism originating as a jocular coinage, apparently by pupils at Eton College, combining a number of Latin word stems. The word was inspired by a line present in various editions of William Lily's (c. 1468–1522) Latin grammars published around the 17th–19th centuries (including the Eton Latin Grammar), in which some nouns commonly used in the genitive case with some verbs like pendo and facio are listed, which express evaluating something as worthless or as previously mentioned; see the reference.