Unfinished business from yesterday’s moorhen-related content: suppose the birds who wanted to body shame the moorhen had decided to call him a fat duck instead of bigfoot? How would they do that? They could say “pato gordo” or “pato gordinho” of course, but is there a shorter option?
Portuguese speakers tend to use the -inho ending on a lot of words as a diminutive, so patinho is little duck, gatinho is little cat and so on. Augmentatives – endings that make a word bigger or stronger are a little rarer and less regular, but substituting – ão for the final o is quite a common way of doing it. Or -ona if it ends in an a.

So in this case, patão would be a chonky duck. You probably won’t hear this very often in Portugal. Things are more likely to be – inho than – ão, but there’s a supermarket in Brazil called patão, and the word does exist in priberam, so it’s not just a Brazilian thing.
I’m trying to think where I’ve heard these kinds of endings: garrafão is a huge bottle, facalhão is a big kitchen knife, and I think I’ve seen it used for outdoor work knives (maybe even a machete?) in some contexts too. Barrigão is used to mean a big belly, whether it’s big because there is a baby in there or because the owner is too fond of Sagres.
You have to be a little careful with these though. I think, because they are quite rare, they might be used for humorous affect and you probably don’t want to accidentally say the wrong thing. Mulherão, for example: how’s that going to come across? Tall woman? Great woman? Fat woman? Coarse woman? It might depend on the context or that tone of voice, so unless you’re supremely confident I’d just leave it out if I were you.
There are other endings too. I can’t really do justice to them without, basically, rewriting this article from Practice Portuguese word for word, so if you want to know more, I’d say toddle on over there and see what the boys have to say on the subject.