Actions taken by employers to keep unions from forming is called what?

The answer to the question presented above would be 'termination'. Actions taken by employers to keep unions from forming would be termination. They use this action in order to scare the employees from uniting against them through laying them off.

I think the term is union busting where they prevent formation of unions. This way, the management will be able to have more control over how things run without union interference. Other methods could be blacklisting them to ensure they won’t work for other companies.