The term "inchoative" is used to describe the beginning or initiation of an action, process, or state. Antonyms for this word would include words that describe the end, completion, or conclusion of such actions or processes. Some examples would be words like "conclusive," "finished," "completed," or "terminated." Other antonyms might include words related to stagnation, inaction, or inactivity, such as "static," "dormant," "idle," or "unproductive." The opposite of "inchoative" depends on the context in which the word is being used and can vary widely based on the intended meaning.