Oooh, what a thread. For what it’s worth, dictionaries record, not dictate, usage. Improper usage is just as likely to make it into the dictionary, if sufficiently common. According to the Introduction in my Webster’s Collegiate, dictionaries are not a good tool for settling arguments of disputed words. Still–
eager for anxious
Eager suggests you are looking forward to the event, anxious indicates apprehension. “I’m so anxious for this new movie to come out!” Arrgh! Then don’t see it!
lightening
If you’re speaking of the meterological phenomenon, it’s lightning without the E.
whom
Along with the I/me quandry, there are those who use “whom” for every usage of “who,” regardless of context. “I’m the one whom did the work.” “Well, I’m the one who’s going to kick your ass.”
jewlary
It’s jewelry, stupid.
deductive vs. inductive
Grr. I hate this one.
colloquial for slang
Am I the only one?
There are a couple that I can’t stand that won’t be very common errors, I fear. I worked with some people (in an engraving shop, no less) who just had a habit of misusing words. For example:
One of the customer service ladies used the term “morphodite” and it took me forever to figure out what she meant. I eventually figured out she meant “hermaphrodite,” and even then, she insisted I was wrong. I was on the verge of bringing in a copy of “The Morphodite” by A.M. Foster and comparing it to a dictionary, but it turned out the dictionary alone did the trick.
In the same business, a woman kept using the word “pissant” as an emotional state. “He’s in a really pissant mood.” I couldn’t make her understand.
How about “forte” pronounced as “fortay?” I have always been under the impression that, pronounced “fortay,” we mean the Italian musical signature for “loudly,” and pronounced “fort,” we mean the French metaphorical definition of “strong point.”
On the other hand, there’s one reverse construction I rather like, except I have no personal taste for using it. How about “reservate?” “I reservated at Chez Frufru at eight o’clock.”