Autistic man here.
Unambiguous communication is really appreciated. No one's a mind-reader, but #ActuallyAutistic people are worse at it than others. It's not just a matter of avoiding ambiguous words, either: please include all the information in your head that might be relevant. My wife Helen doesn't do this — every time she opens her mouth to speak, she leaves out one central piece of information — and it drives me scatty sometimes.