A few words in this section that I never use or have ever heard of. I use nawr for now
It's a North/South thing. Rŵan in the North, nawr in the South. They're both contractions of a longer phrase that I can't remember now. Stick to using one, but you need to recognise the other when you hear it spoken by other people.
rŵan is from yr awr hon "this hour"
nawr is from yn awr "in (the/this) hour"
You sometimes see and hear yn awr in formal contexts. I hear it at the till when I go to the supermarket!
Synonyms occur in every language, I think :)
Like English has "gasoline / petrol, flashlight / torch, sidewalk / pavement, fall / autumn, eraser / rubber" between US and UK, for example.
As they say just above this post, it's a difference between the North & South dialects