Stoic
My dictionary says failure means that some fault, or lack of fuel, has caused a powerplant to stop functioning altogether, unexpectedly.
But I can shut down one in flight at any time, without a failure, if I estimate that I should. Example temperature warning or vibration indicated. That may be a sensor fault, only. I take a precaution.
If "semantics" means "no difference" I do not agree that this is semantics.