"She is not excited."

Translation: Dyw hi ddim yn gyffrous.

[StephenDunscombe]

My dictionaries give "cyffrous" as "exciting" rather than "excited". Is it used for both?

[ibisc]

It can be. As with other terms and expressions, there are other ways of saying it, but this one is simple and commonly used and understood.

[RozieToez]

How would you say "excited" if context wasn't going to make clear you didn't mean "exciting"?

[ibisc]

I'd stick with cyffrous, I think... If somebody was excited as in 'agitated' then perhaps cynhyrfus/cyhyrflyd/berwedig. If excited by something, then maybe even wedi cyffro/cynhyrfu.

In the wild it doesn't really come up as a problem - there is a context of some sort.