...We all know that one side's terrorists are another side's freedom fighters...
Suppose big Country X provides arms to little Country y's native "freedom fighters", who do certain scary things, ("for freedom!"), which goes on for a decade or so, but then Country y's freedom fighters wind up fighting against Country X, doing the same scary things, which Country X now labels "terrorism".
Meanwhile Country y's fighters still consider themselves freedom fighters, and let's suppose that for the average fighter from Country y the daily routine never changed, they still get up in the morning, report in, and follow orders to get the same-old same old scary things done.
That'd be a subjective usage of the term "terrorism".
Is there a non-subjective usage of the term, one that both sides could agree upon as unequivocally terrorism, irrespective of the cause or target?
If not, is there any non-subjective term, (which describes the job of doing the scary things Country y's fighters do), that both sides would always agree upon?