"Deadon" refers to something that is extremely accurate or precise. Its antonyms would be words that describe inaccuracy or imprecision. These could include words such as vague, inaccurate, imprecise, rough, approximate, or fuzzy. Another possible antonym for "deadon" could be "off-target," indicating that the aim or goal was missed. Other antonyms could include words such as mistaken, incorrect, erroneous, or flawed, indicating that the information or measurement provided is incorrect or flawed. Thus, the antonyms for "deadon" are words that indicate a lack of accuracy, precision, or correctness.