Antonyms for the word "most full length" could include words like abbreviated, condensed, shortened, brief, or truncated. These words suggest a shorter length or duration than the original phrase, indicating that there is less of something or that it has been reduced in some way. For example, an abbreviated version of a book is much shorter than the full-length version, while a truncated movie may leave out entire scenes in order to fit it into a specific time frame. In contrast, the phrase "most full-length" would imply that something is as lengthy or complete as possible.