Interesting question, King. Political murder was quite common in Imperial Rome (among other situations), but since it's unlikely that Tacitus or Suetonius was familiar with Arabic (not to mention their predating Islam by many centuries), they must have used a word other than "assassination" for the concept.
Maybe they just used "kill," "murder," or synonyms, and perhaps "regicide" where applicable.
The distinction of the word "assassin" lies in the maniacal enthusiasm with which the killer functions.
One assumes that other killers operate on hate, or emotionless indifference, or even with a pride of expertise in their craft, but only in the assassin does one see a rapturous glee for the process. Chemically induced, originally. I don't know if the current crop of suicide bombers is given even that palliative.
One thing is abundantly clear; the epicenter of victimhood is a person inundated and awash in ignorance and false teachings. There is so much concentrated stupidity and weak-mindedness that it is surprising that explosives are needed at all. These pathetic creatures are the very antithesis of our technological "smart bombs."
They function as a new definition for the concept of "dumb bomb." Be careful not to get any of their ill-contained stupidity on ya.