After a little while pondering the ponderous, I think I've come to a fairly concise (well, as concise as I ever get) definition of the two:
Frugality is being careful with your own money.
Cheapskatery is being wasteful with other people's money.
Cheapskatery is being wasteful with other people's money.
Let's break this down a little further.
When you are frugal, you take the time to be mindful of the way you use the money that comes into your life. It doesn't mean you never spend money; rather, it means you consider what's important to you, and put most of your money toward those important things. Frugality is a vital part of responsible adult behavior, and teaching people how to be frugal is part of the purpose of this blog. You can take pride in becoming frugal.
You should take no pride, however, in being called a cheapskate. Though cheapskatery may look similar to frugality on the surface, it is markedly different under the skin. When you seek to be frugal, you're trying to make the most of your money so that your spending comes in line with your personal values. Cheapskates, on the other hand, try to save their money at any and all costs. Often they seek to save their own money by forcing other people to spend theirs instead -- for instance, they may have enough money to buy lunch, but try to get other people to buy it for them so they can save their own cash. BIG HINT, KIDS: this is scummy behavior.
And you'd better not justify your scummy behavior in front of me by saying, "Well, I'm poor and other people can afford it more," or some such rich bull feces, or I'll kick your cheap little butt. Because even if you save enough on other people's backs to become rich, you'll have developed a lifelong habit of mooching off other people to get there, and believe me, you'll go right on being a scummy cheapskate even when you have millions in the bank. Do you really want to become a modern-day Hetty Green? (No, no you don't.)
OK, maybe you're still not entirely clear on the concept. Let me provide you with a few Tales of the Cheap and Scummy, and some alternative frugal options.
CHEAPO: One of my dad's college roommates, a notorious cheapskate, wanted to take his girlfriend out on a date. Since my dad had a nice car, Mr. Cheapskate approached him to ask if he could borrow the car for a date night. Dad agreed; his only requirement was that his roommate pay for the gasoline he used. Well, Mr. Cheapskate took his date to a night on the town 45 miles away, and when he returned the car, which was running on fumes, he handed my dad 25 cents as his gas contribution. (Granted, this was at a time when gas cost approximately 40 cents per gallon, but cars also burned a lot more gas than they do now.)
FRUGAL: Figure out the social calculus of this exchange for half a second. You're much more likely to deal with your (annoyed) roomie every day than you are with the girl you're trying to impress for one night, so it makes the most logical sense to stay on good terms with your roommate. If you have enough money to take your girl on a nice date, you have enough money to fill the tank of the car you borrowed. And you should fill the tank, even if the tank wasn't full to start with. It's a way of expressing your thanks for your roommate's thoughtfulness and generosity at loaning you the car at all. If you don't have enough money for both the night out and the gasoline, maybe you should consider a less expensive date, or one you can go on closer to home. Or you should put the date on hold until you have a little more money. Learning to say "no" to things you can't afford or don't want is one of the first skills of frugal living.
CHEAPO: I know of a woman who loves going out to eat. She used to approach all her friends with an idea for lunch or dinner: "Let's get Mexican!" "Let's go get sushi!" "Who wants Indian?" They'd agree and go off to eat together, but when the bill arrived, the woman who suggested the outing in the first place would say sadly, "Oh, but I don't have enough money to cover this." Her friends would cover her share, first empathetically, then begrudgingly. Soon some of them learned not to accept her constant, thinly-veiled invitations to pay for her meals.
FRUGAL: If you can't pay for your own meal, don't instigate a mass lunch or dinner date in the first place. Really want to go out with friends? Then suggest a place you can afford. If you don't want to be stuck paying for someone else's meal, request separate checks before you even sit down. And if you end up going to a restaurant where you look over the prices and determine that you can't pay for the meal, it's perfectly acceptable to bow out. If you get into a situation where someone insists on paying for your meal, then you pay for that person's meal on another occasion. (Don't just promise to pay. DO IT.)
CHEAPO: My grandfather, who was in the ski troops during World War II, had a heavy military ski coat -- one of a very few things he'd kept from his war experiences. A relative asked to borrow that coat in order to go on a skiing trip with his brother, and my grandfather agreed to lend it to him. Months went by, and the coat did not return. Finally my grandfather asked about it. "Well," said the cheapskate relative, "it's not like you can use it any more. I gave it to my brother. He could really use a nice heavy skiing coat like that."
FRUGAL: YOU DO NOT GIVE AWAY OTHER PEOPLE'S POSSESSIONS. EVER. EVER!! I can't possibly emphasize this enough. It doesn't matter if they can't use them any more (my grandfather had lost a leg in the war, which made it difficult for him to ski); it's not up to you to make that decision because IT'S NOT YOURS TO GIVE AWAY. If you borrow possessions from people (books, movies, music, small appliances, tools, anything), take good care of them, keep track of them and return them promptly. Do not give them away, do not loan them out to other people, and FOR THE LUVVA PETE don't force people to come to you to get their stuff back, you cheap jerk.
CHEAPO: A relative of mine called to ask if his in-laws could stay with my mother for one night while they dropped off a son at school. She, assuming it would be the son and his two parents, agreed. But on the evening of the agreed-upon day, a family of eight arrived on my mother's doorstep and proceeded to take over the entire ground floor, including the kitchen. The next morning, the father of the family decided to change his plans (I guess staying in a home for free seemed better than camping to him), and announced to my mother that they would be extending their stay a little longer. "Longer" turned out to be a full eight days. During this time there was no way for my mother or sister to make meals, and the family did not invite their hosts to eat with them. When these cheap locusts finally decamped (to their credit, at least they had the common decency to clean up after themselves), they left my mother with a housewarming gift that cost approximately 75 cents. The relative who had originally called in the favor, who had no idea what his in-laws were doing, was mortified at their behavior.
FRUGAL: Sharing one's home is one of the most generous things anyone can do. If someone is hospitable enough to put you up in his or her home, stay only the agreed-upon time and no longer. You don't have the right to renegotiate terms once you're within the walls. You don't have the right to take over and monopolize household resources such as the kitchen. You don't have the right to invite additional people to stay with you. And at bare minimum, send your host a thank-you note after your stay. Again, if you can't afford to pay for an extended stay for the whole family and they don't need to be there, maybe you should leave some of them at home. And yes, if you plan on staying that long with that many people, camping is a much more frugal choice.
I think I've made my point: it's perfectly acceptable to be frugal, but the whole world hates a cheapskate. Don't be that guy. Be careful with your money, but don't save your resources by forcing other people to spend theirs, or you deserve to have your cheap butt kicked from here to China.