I DON'T FEAR LONG WORDS but Hippopotomonstrosesquippedaliophobia is one of the longest words in the dictionary  and, ironically, it is the name for a fear of long words. Sesquipedalophobia is another term for the phobia.

The American Psychiatric Association doesn’t officially recognize this phobia. Instead, hippopotomonstrosesquippedaliophobia is considered a social phobia.

The new edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) outlines a very specific definition for social phobias. Medical professionals use the DSM-5 to help them make diagnoses.