A disciplinary term

Some discourse-theory light maybe?

As in: Rather than describing an actual object (a particular form of practice that terrifies people, which leads into all sorts of debates about who can be a terrorist, is the pervasive violence enacted by men against women 'terroristic', is the precarised labour market a form of structural terrorism, etc), 'terrorism' may be seen as a disciplinary term in political discourse that serves to delegitimate political violence usually (but not always) enacted by the weaker actor in a given conflict.

To call a particular kind of political (or sometimes economic) violence as 'terrorism' isn't to describe it, but to condemn it, to render it evil, thus in turn making it more easily attackable.

The reason to use discourse theory is that any attempt to define terrorism I've seen so far runs up against one of two problems: Either it expands the term to such an extent that it becomes completely devoid of any particular meaning (all violence is terroristic!), or it becomes too specific so that we cannot reasonably include phenomena that in everyday usage could certainly be understood as terrorism (such as the US state department's definition ["The term terrorism means premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents, usually intended to influence an audience."] which would a priori exclude 'official' state terrorism).