Depends on what his or her name is. (Ba dum dum)
What, you want a serious answer? I mean given that P W Singer and Elina Noor begin their Op-Ed with a comparison between Muslim radicals and Nazis and the imperial Japanese during WWII, I figured this had to be a joke. Alas, no.
Singer and Noor basically argue that to call terrorists--and it's clear that they are limiting their definition of terrorist to those of Arabic Islam--anything other than that is to give them undeserved respect, especially when it comes to the use of the word "jihadi."
Singer and Noor begin this way:
First, to call a terrorist a “jihadist” or “jihadi” effectively puts any campaign against terrorism into the framework of an existential battle between the West and Islam. This feeds into the worldview propagated by Al Qaeda. It also serves to isolate the tens of millions of Muslims who condemn the violence that has been perpetrated in the name of Islam.First of all, the US framed this as an existential battle in the first place--remember Bush calling it a crusade? Secondly, the term is an accurate one, even if we're uncomfortable with the implications. Al Qaeda is hardly the first organization to wage asymmetrical warfare against a more powerful enemy and use a radical reading of their scripture to justify their actions.
Furthermore, many who refer to themselves as jihadis are not part of Al Qaeda, and this is the real problem with their argument. Are Palestinians who are arguing for a two-state solution jihadists? Yep. Are they the same as al Qaeda in Iraq or the Taliban? Nope. And what about groups that are hybrids? Fatah was a terrorist organization which became, for a while, the governing force in Palestine. Hamas seems to be in a transformational stage. Hezbollah, depending on who you ask, is either a terrorist group trying to destroy Israel, or a group of freedom fighters who pushed Israel out of Lebanon, or something in between.
My point in all this is not to argue that any of these groups are peaceful--it's that if there's a problem with the term jihadi, it's that the term is too generic, that it can cover far too wide a group of people, including those who feel they have legitimate grievances against the government that rules over them, and are struggling against that oppression.
So why not use the word terrorist to cover everyone? Part of the problem, I think, is that terrorist as a term has come to be synonymous with Arab Muslim extremism, thanks to the way it's been used by the west. It seems to me that terrorist acts are committed against western countries or their allies, and other forms of the same type of violence that don't involve us directly get some other kind of euphemism.
I'm far more in favor of using more specific terms--call the groups by their names, and talk about the issues that are driving the violence. Not all struggles are the same, after all--some are based in legitimate differences, and have turned violent only after decades of oppressive behavior by the powerful over the powerless. To lump those groups in with those who are fomenting violence for the sake of chaos, or who are engaged in an existential struggle between the West and Islam is neither honest nor beneficial to the discussion.