Hi - no. A ragout is a sort of meat and vegetable stew - I assume French; and a ragu is a really thick, yummy, rich, Italian tomato-and-meat sauce to coat pasta with. I did a search just a few mins ago on 'ragu recipes' and the first page came up with recipes for ragu by e.g. Delia, Jamie Oliver and Nigella; although my searches may be slanted towards the British. Ragu is nearly always spelt with a lower case 'r' and often has what looks like a grave accent on the u.
Doing a 'define ragu' search gave me a wikipedia entry for ragu sauce. (I did also see a commercial jar called Ragu - I wonder if it bears any resemblance to the real thing? It certainly didn't look the right colour!) I can't remember which dictionaries I found ragu in first time round, sorry, but it was there. I pronounce ragout and ragu in the same way but probably the cognoscenti don't.

I put "ragu" in with confidence (being interested in cookery). It's a rich Italian sauce containing minced meat. I've found it in a couple of dictionaries and a BBC page.
Dunger seems to have three possible meanings, according to the dictionaries (someone involved in cloth preparation; a type of machine; an old car (slang)).
Denga is an old Russian coin.

Hope I didn't just mistype the words when entering them into the game!

(As in e.g. Welsh 'tref' changing to 'y dref'.) Not accepted in a random puzzle. It isn't a word I've ever used, but it's in Collins - though not Chambers - and a Google search brings up several references. What is the criterion for acceptability? Is a specific dictionary used?