The action or practice of using long, complex words in speech or writing, often to appear more intelligent or to obscure the meaning. This can make communication harder to understand and is sometimes seen as pretentious.
His blog posts were criticized for their sesquipedalianism, as he seemed more interested in showcasing his vocabulary than in making his ideas accessible to readers.
Floccinaucinihilipilification is the act or habit of describing or regarding something as unimportant, of having no value, or of being worthless.
The critic's review was filled with floccinaucinihilipilification, belittling every aspect of the author's hard work.