You think you know a word until you actually learn what it really means

The first word is Spaz. Tiger Woods said this following the Master after he didn't do as well as he hoped:

I was so in control from tee to green, the best I've played for years... But as soon as I got on the green I was a spaz

I've used the word spaz, not recently, but i have used it. I have no problem with Woods say spaz. But according to the BBC, many disability groups have spoken out against Woods' usage of said word and he has apologised since then. At no point have i ever know or thought that spaz was used to describe individuals with cerebral palsy. I googled the definition and it came back with the following:

One who is considered clumsy or inept.

I agree with this definition and i think this basically the common usage of the word and what Woods meant when he said it. Also considered is the key to this definition. Now i consider certain people to be clumsy or inept. It doesn't actually mean they are. I just consider them to be. Others might disagree.

There are two other words that i just found out what they really mean. Both come by Gene Weingarten. The first word is scumbag which I've always thought meant slimy jerk. Somebody you don't want to know and be around. Now I've always thought it was more or less family safe. The new york times also thought so to but found out the hard way in a manner of speaking. Lets just say it means something else. Slate explains.

The next word is unprintable by the Washington post. It is schmuck. Again i thought this had a more or less family definition. I was wrong again.

Now I'm arguing that all three words have had their common usage definition changed over the course of the years and all have different meaning then they use to have. That's the great thing about the English language. It adapts to a change in society rather easy. English is built on the common usage of words. All of these words in my mind can be used in polite company.