As I am wont to do on a weekday night, I was reading up on a few top ten list with a historical inclination yesterday when I suddenly felt like writing my own lists.So to officially start off my first list, here's one which should be no surprise to anyone who knows me: A list on the improper use of certain words.InflammablePeople think it means: Something which will not burst into flames
Acutually means: Inflammable actually means flammable. An item which is nonflammable is something that does not burst into flames, ergo causing you millions in damages. To quote Doctor Nick Riviera: Inflammable means flammable? What a country! Ironic People think it means: A coincidental happening
Actually means: An outcome of events contrary to was expected. Really, I hear the words 'ironic' and even 'random' being thrown around way too much nowadays; as if they were 'stem-cell words', capable of differentiating into variable meanings. Irregardless People think it means: Regardless
Acutually means: Nothing. The confusion stems from the usage of words like irrespective and irresponsible, but regardless already has the -less at the end to bring forth the meaning 'not worth regarding'. As such, Irregardless is actually a non-standard word and one you won't find in the dictionary; yet it is commonly used by people everywhere. Nonplussed People think it means: Not worried, indifferent
Actually means: Utterly perplexed. It would seem that the misunderstanding started when people started guessing what it meant based on how it sounds within the context of a sentence. Bemused People think it means: Slightly amused
Actually means: Confused. Honestly, the word itself is to be blamed here as it really does sound like someone is only marginally amused when you say "He seems bemused". Penultimate
People think it means: One step above ultimate.
Actually means: Next to last. A penult is the second to last syllable in a word. Imagine the confusion caused when you read a review wherein the reviewer has nothing but good things to say about the reviewed item and suddenly says something along the lines of "It is the penultimate technological gadget". Plethora People think it means: A lot of something.
Actually means: This might be splitting hairs a bit but it doesn't just mean a large quantity. A plethora of something means an excess or overabundance. Farther / Further
People think it means: The same thing
Actually means: Farther conveys advancement in distance whereas further denotes an advancement to a greater degree. For example: The farther I travel down the road, the further behind schedule I'll be. Exempli gratia / Id est (e.g. and i.e.)
People think it means: The same thing, which is: for example
Actually means: e.g. means for example. However, i.e. basically means 'which is to say' or 'in other words'.
"His heart sunk as he read his results slip; i.e. he was devastated." Atheist / Agnostic People think it means: Not believing in the existence of a God
Actually means: An atheist doesn't believe in the existance of a God. An agnostic isn't someone who necessarily does not believe in God, but one who believes that there is no way, or no means of knowledge, to prove the existence of God. Kuhanesh | 
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