Antonyms for the phrase "put finishing touches on" can vary depending on the context, but they generally involve actions that disrupt or hinder the completion of a project. Some possible antonyms could include "neglect," "abandon," "ruin," or "destroy." Neglect would mean failing to complete a project or leaving it unfinished, while abandoning it would involve discontinuing the project altogether. Ruining or destroying the project would mean causing harm or damage to the work that had already been done. Other antonyms could include "starting from scratch," "undoing," or "negating," all of which would involve undoing or erasing previous progress made on the project.