Quaggy is related to quagmire, a word for a patch of wet land that feels soft underfoot, but etymologists are not sure where the first half of the latter word originates. Some have suggested that quag might be imitative, echoing the soft, mushy sound that wet ground makes when you walk on it. Both quagmire and the shorter noun quag first appeared in English in the 1580s, while quaggy, which can describe land as well as other things lacking firmness, appeared about thirty years later.
