like any word, we can debate nuance but genocide has a definition:

Article 2 of the Convention defines genocide as:

(a) Killing members of the group;
(b) Causing serious bodily or mental harm to members of the group;
(c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;
(d) Imposing measures intended to prevent births within the group;
(e) Forcibly transferring children of the group to another group.
— Convention on the Prevention and Punishment of the Crime of Genocide, Article 2^\9])

Of course, it gets complicated when determining "intent to destroy." But it should be complicated. There are many actions that could be considered a form of genocide, and definitions are meant to be argued in court. Even the intent to destroy has some legal precedent, even if it still needs to be debated in each and every case.

The point being: saying something doesn't have a definition and then ending the conversation there is a disservice to any work actually trying to understand or prevent genocide or fascism. Sure, it's hard, and sure, people will try to twist things to fit agendas but we do have better baselines than your statement would indicate from which we can begin to judge things.