undone bowtie
A bowtie that has been unhooked or unraveled back into a ribbon, but is still being worn around the wearer's neck.
If the bowtie is still tied but is hanging loosely, use loose bowtie instead.
If the ribbon is not clearly a former bowtie, use undone neck ribbon instead, as in post #3198225.
See also
This tag implicates bowtie (learn more).