@Saetva , on the job application I wrote reason for leaving: terminated, found not at fault by Unemployment (which is the case for my termination because I filed an appeal with unemployment explaining the discrimination). You could also write, "terminated, would be happy to discuss this further if interviewed."
In the interview, I went pretty broad. One of my termination reasons listed on the termination letter was this project where the timelines got messed up and I was able to say, "my official termination reason was ___ (this project)." The job I'm doing and was interviewing for is the same, and they've done similar projects so when I explained that reason they contextually knew it was rather petty.
I went on to say that I felt like my immediate supervisor felt I wasn't supporting her vision, but at the time, it felt as if she wasn't communicating what she wanted of me. This is somewhat true, although it doesn't explain the situation. It's the line I plan to use again in the future. In the future, I will also probably explain that my supervisor was receiving a lot of pressure because she was new and walked in to a program had been failing for 3 years and I think that pressure affected her leadership. The truth is, even if my coworkers hadn't been spreading rumors about me to her and others, she was looking for a scapegoat because the goals they'd set for her were unrealistic and her ability to meet them was nil.
The interviewers asked, "Well what was your role? What could you have done differently?" That was hard because I had tried so hard to do differently, had discussions with other supervisors, with HR, with coworkers, with friends, with my therapist, filed for accommodations, expressed how much I actually like this work, etc. So I was teary-eyed and just said something like, "We should have been meeting more frequently and trying to communicate through that." I didn't think these answers were good enough, but I got the job, so it must have been okay. Turns out this organization is very calm, capable, and has other people employed who were previously terminated.
I think keeping neutral language answering the why question and keeping it broad. It turns out there's lots of people in the workforce who have been terminated from other places. (Both my therapists referenced they'd been previously terminated. As have 3 of my current teammates on a team of 6). You won't be the only one they've interviewed who has been, but making sure you don't get bogged down in the emotions of it when you explain and obviously not seeming like you're bad-mouthing the previous employer will be important.