How do you say countess in Gaelic?

There isn't one single word for "countess" in Gaelic (either Scottish Gaelic or Irish Gaelic). The translation would depend on the context and the specific nuance you want to convey. You would likely use a descriptive phrase, something like:

* Scottish Gaelic: A phrase like "ban-co-ìmpire" (woman-co-emperor) might be used, although it's not a direct translation and would be somewhat unusual. A more natural translation would involve describing the person's rank and status.

* Irish Gaelic: Similar to Scottish Gaelic, a descriptive phrase would be necessary. Something implying "lady of the count" or "wife of the count" would be appropriate, but a direct, single-word equivalent does not exist.

To get the most accurate translation, you'd need to provide the full sentence or context where you intend to use the word "countess".