I'm cool with using the word Deepfake for text. Generated text should generally be referred to in the derogatory, considering it very rarely adds anything of value.
The closest analogue for text I can think of is when you use an LLM to write in the style of someone else, like Shakespeare. But "deepfake" is a stretch because AI-generated text in someone's style is not particularly convincing that it actually came from them, and wasn't too hard to do manually before. Plus doesn't raise the same ethical questions.