In any move, you can either replace a letter, add a letter, remove a letter, split a word or combine two words. These are the five valid moves, and only one of these can be applied in a move.
After each move, each of the resulting words must be valid by itself, even if it makes no sense as a phrase. To level the playing field, only words found on Dictionary.com are considered valid. No proper nouns, abbreviations, prefixes or suffixes allowed. (However, words like jack, john, jane etc. are allowed as they are used as common nouns too.) Alternate spellings and archaic words are permitted, but words referring to specific persons, places or events are not valid.
You may only add a letter to an existing word, but a new letter (such as a or I) cannot create a new word separately. Likewise, you cannot drop a letter from a one-letter word to remove it altogether.
The problem is that two of the words I chose Perfect and Answer appeared to be word islands. By this I mean that there doesn't appear to be any way to move from those words to any other words following the rules above (except, of course for the trivial case of adding an S to the end which doesn't help the transition to anything else).
What is the shortest word that anyone can find which is also a word island? (I'll accept answers where it is one of a pair of words where the only valid moves are back and forwards between them)
Of course, I would be glad to hear if my two examples are not, in fact, islands after all.