The word "buttons down" typically refers to the action of fastening buttons on clothing, but its antonyms can vary depending on the context. In the sense of opening or unfastening buttons, antonyms might include "undoes," "unbuttons," "opens up," "releases," or "loosens." In other contexts, "buttons down" might refer to a person becoming more reserved or serious, in which case antonyms could include "opens up," "lightens up," "relaxes," "unwinds," or "lets loose." Similarly, if "buttons down" refers to organizing or tidying up, antonyms could include "disorganizes," "messes up," "clutters," or "scatters.