1. (noun) When one asks a teacher, parent, etc., how to spell a word and is told to look up the word in the dictionary, usually either because the teacher, parent, etc. is too lazy to impart the word's spelling or doesn't know how to spell it themself. Spellpidity is short for "spelling stupidity", because you must know how a word is spelled in order to search for it in a dictionary.
Kindergartener: "How do you spell 'dachshund'?
Teacher: "Look it up in the dictionary."
The Kindergartener has just experienced spellpidity.