Starting from a genuine English word, our objective is to reach a word that has the exact opposite meaning (antonym) and contains the same number of letters as the original word, following precisely the same rules as Laddergrams. All the words in the intermediate steps must be proper English words (meaning no slangs or abbreviations).

What N-letter English word(s) generate its/their antonym(s) in a minimum number of steps, whenever N=4, 5, 6, 7, 8.