There aren't very many words that end in -uggle. Smuggle, snuggle, struggle, juggle and . . . that's all I've got. Well, there's "puggle", the made-up name of a dog, I think a beagle/pug mutt. And "muggle", another made-up thing. It's a funny-sounding thing, "uggle". Do the -uggle words have a common language of origin?