In general, words with opposite meanings are called antonyms. Is there a word that describes the subset of antonyms that are different only by a prefix where the prefix negates the meaning of the root word?
cold are antonyms, but don't share a root and would not be described by the term I am looking for.
unpaired are antonyms and share the same root
paired. These words would be described by the term I am looking for.
Lost positives would be a special case of this type of word where only the negated sense of the word is in use, e.g.
disgruntled is a commonly used word, but
gruntled is not.
A bonus answer would point to a list of such negating prefixes.