Hippopotomonstrosesquipedaliophobia

HIPPOPOTOMONSTROSESQUIPEDALIOPHOBIA (/hi-pe-po-tə-‘mon-strə-se-skwi-pi-dei-liə-fo-bia/), noun.
DEFINITION: fear of long words.
EXAMPLE: His hippopotomonstrosesquipedaliophobia prevented him from using words like hippopotomonstrosesquipedaliophobia.