Not all words beginning in ‘un’ are the opposite of the letters that come in front of ‘un’. Or at least, those words are rarely, if ever, used (nobody ever says flappable or couth). Below are several ‘un’ words, many of which don’t mean anything if you remove the ‘un‘. (the exceptions are unabashed and unassailable).
Upon seeing this word, you may imagine lips flapping—or not flapping at all. But unflappable has nothing to do with lips, wings, or just about anything that flaps. A person who is unflappable never loses his or her cool during a stressful situation. It’s sort of like “being Zen”. That said, people who are poised rarely tend to flap their lips—regardless of the situation.
Something disruptive that you can’t get under control is unruly. A classroom can be unruly (think of a 6th grade class ten minutes before lunch), and so can a crowd of angry people (think of any of the recent protests you’ve seen).
“Gainly” used to mean graceful. The word has fallen out of common use, but not its counterpart ungainly, which means lacking in grace. An NBA basketball player trying out ballet moves, a hippopotamus on roller skates, and anybody trying to walk barefoot across ice are all ungainly.
Lacking manners? Do you say inappropriate things at inappropriate times? Well, hopefully not—or you’d could be rightly labeled uncouth. An uncouth person is tactless and rude. Some GRE words that roughly mean the same thing are boorish, indecorous, and churlish.
If you assail something, you attack it, either physically or verbally. If something is unassailable, on the other hand, it cannot be subjected to a verbal attack, or any attack in general. If a person’s logic is unassailable, you better not try to argue with that person. If a fortress is unassailable, you better not attack it (though I’m guessing your fortress attacking days).
To be abashed is to be ashamed or embarrassed over something. To be unabashed is to not feel any shame over something—something that many others might be a little more hesitant embracing. Let’s say you actually think one of Justin Bieber’s songs are catchy. You won’t go around proclaiming your love for the mop-headed Canuck crooner…unless, you are unabashed in your admiration for the singer. In that case, your walls will be festooned with posters of Justin Bieber and you’ll never miss an opportunity to tell others how the singer is a genius.
On a personal note, I have an unabashed love for vocabulary—though I’ve tried to tone it down by not using GRE words when talking to strangers.