long; characterized by the use of long words
"Plus he has a weakness for what we can mischievously call sesquipedalian excess: Look out for such terms as 'epiphenomenal,' 'diegetic' and 'proprioceptive.'" Jabari Asim, Washington Post, November 19, 2000
About the word:
Sesquipedalian pleases in part because it is what it describes: a long word for long words. The Latin sesquipedalis translates as "foot-and-a-half long." That's the way the Roman lyric poet Horace used it when he advised young poets to use common speech instead of sesquipedalia verba ("words a-foot-and-a-half long"). This concept is similar to the modern term "20-dollar word."