A guild is a trade union. To gild is to cover with a thin layer of gold. A search on Guild* + Gild* gets 114 hits in OhioLINK: Not all of them are typos, but quite a few are. Unfortunately for our purposes, gild is an alternate spelling for guild (although the reverse is not the case). Gilding is what librarians or bookbinders do when they emboss gold letters on the spine of a book. This word often turns up in my own workplace as guilding, but whenever it does, I try and let my colleagues know that U is just gilding the lily.
(Gilded Flicker in flight, from Wikimedia Commons.)