When I was part-time teaching, I somehow got two sociology classes at a nearby community college. They were an awful lot of work (especially as the only sociology class I ever took was an introductory class several decades before), but we were able to do some interesting stuff.
One day, we tried to define the word "terrorism." My main rule was that I would not accept any student definition which could also be applied to the American government. I thought this would be fun and a little difficult. What I did not expect, however, was that we would not be able to come up with any definition at all which wouldn't also describe the Allieds in World War II. And believe me, we tried...for a good 45 minutes.
The lesson we learned is that the word terrorism only really had any specificity at all as a political label. Using force to instil terror? That happens all the time, from insurgents operating a road bomb to the US government anti-drug policy. Position is everything. The other thing we learned was equally fun: as a species, we are certainly a violent, nasty lot...and this is deeply instilled throughout our history and society.
Having said that, however, there is a certain "I know it when I see it" element to terrorism which is undeniable. The key is to not let the obvious emotional connotations overcome our logic and common sense. The concept of terrorism is not a legitimate excuse to not think.
Take the recent church shooting in South Carolina. It is certainly, undeniably terrorism. However, we can't stop at just labeling it as such.
This particular type of terrorism is one that's easy to trace. The abundance of and easy access to guns is certainly an issue, and to not address it would be disingenuous. The racist roots of the attack are also pretty clear and obvious, from the apartheid-era South Africa flag the shooter added to his jacket to the Confederate battle flag which is near-omnipresent in the state (and yes, the Civil War was about slavery; the South Carolina secession notice specifically mentioned slavery).
Now I know that treating something as terrorism can lead to very knee-jerk reactions (see The Patriot Act, the never-ending invasions of Iraq and Afghanistan, anything done by the NSA, and so on)...that's clearly not the best option. But neither is pretending there are no grand problems at the root of the initial act of violence. So, instead of discounting terrorism or responding with corresponding terror, I would like to suggest we look honestly at the actual causes and try to address them. Try admitting that weaponry is a problem and then work to remove it from the equation. Admit that ignorance is running rampant and then work to eliminate its sources. You know, stop these things before they start.
Yeah, I know...probably seems too crazy to work, huh?