On your computer right now, you can probably click on the "Edit" menu; and one of the first options will be "Undo". These are closely associated words. But how close are they in a word ladder?
Challenge: Change EDIT to UNDO by changing one letter at a time. Each intermediate word must be a valid word in (modern) English.
The accepted answer will be:
The shortest chain of words that uses only uncapitalized words (i.e., no proper nouns) in Merriam-Webster Dictionary (and their pluralizations, tenses, etc.)
If no such answer is found, the shortest chain of words including proper nouns from the Merriam-Webster Dictionary.
If no such answer is found, the shortest chain of words using any other modern English dictionary, including proper nouns.
Acronyms are not allowed. I know of a solution satisfying criterion #1, which uses one relatively obscure word.
EDIT: somehow I forgot that there were words other than nouns. My intent was only to prohibit proper nouns in Criterion #1, not to prohibit any words other than nouns.