Merriam knows, he says quite a bit about sarcasm:
Funtion: noun (why did I have the sense it's a verb?)
Etymology: (and here I thought THAT was the science of bugs?) French or Late Latin; French sarcasme, from Late Latin sarcasmos, from Greek sarkasmos, from sarkazein to tear flesh, bite the lips in rage, sneer
1 a) sharp and often satirical or ironic utterance designed to cut or give pain
2 a) a mode of satirical wit depending for its effect on bitter, caustic, and often ironic language that is usually directed against an individual
I've come to look at the word and it's usage much differently than I did at one time (the times when I used it to my advantage, to be exact). I now see it as a linguistic form intended to accomplish a number of things, most of which aren't nice, and most of which are veiled - ie, Oh ... I was only kidding.
Sarcasm does not build bridges, but tears them down... It does not mend fences, but opens even wider breaches... It does not enhance another's worth, but undermines it... It does not honor or affirm either the sarcastic one, or their victim ...
There are some (proponents of sarcasm) that would say it's nothing more than harmless wit. Au contrare! Merriam says that "wit" is reasoning power, or astuteness of perception or judgment; or an imaginatively perceptive and articulate individual especially skilled in banter or persiflage (persiflage?). There can be a satircal component to wit, which is where it crosses from good-natured insightfulness to the sneering of sarcasm.
Quite literally, sarcasm is tethered tightly to the heart and the motives therein. We all know when we mean to make a point and/or land a blow in some sarcastic fashion. It's as much about looks as it is about words. Sarcasm is never accidental!
Why do we use sarcasm, anyway? A few possible answers, but hardly an exhaustive list:
... It's a means of passive aggression. We say something sharp or cutting as if to be funny, when in reality we're hiding our resentment or contempt.
... It's a way of saying something unkind or down-right mean about something or someone that we can laugh off as a joke if confronted.
... It's a distancing measure we use that let's people know they're not free or safe to say what they think or feel about what I just said (unless, of course, they want a dose of my sarcasm to get on them too).
... It's a form of verbal abuse, as though the hearer(s) deserve it.
... It's a flawed attempt to be cute or funny.
Before I'm tempted to use a sarcastic tone or phrase, I hope and pray I will not soon forget that it creates a sarChasm.
Now that's a noun, for sure!