Currently, there are tags for unfastened, unbuttoned, unzipped and untied, as well as partially_* version of these tags. However, in order to tag and search for images that contain these features, it would be necessary to identify whether the clothes was using zipper, button, or any other fastening technologies to keep the cloth together before it was undid.
Sometimes, the image may not include detail on whether the cloth was supposed to be keep together using zipper or button, like post #2984076, post #2974135, post #2974967, post #2974811, or that the cloth was supposed to be keep together using some kind of unknown technologies. In these cases, it would be hard to tag and search the image as it would be up to the tagger's decision to decide whether it is supposed to be a buttoned cloth or a cloth that use zipper, or the tagger may not tag such image with un*ed tag as all because of lack of clarity regarding which type of method was it supposed to be.
Therefore, I suggest the use of two tag "undone" and "partially_undone" so that all images can be tagged as such even when it is not clear about whether the image was using zipper or button.