It is an icon of a broken link. It is angled at 45 degrees, with a single, straight line sitting above two broken chain links sitting side-by-side. the upper corner section of the links are missing, denoting that the link is broken.
Related to Broken Link Icon
Related icons are the icons with matching tags, as well as all messaging icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors