You’ve been saying it in the wrong context forever and now it’s time to stop.
1.

What you think it means: A way to add emphasis to any sentence, as in: “Justin Bieber’s pants are literally the worst thing ever.”

What it actually means: In a literal or strict sense, i.e., something that really happened, without exaggeration or inaccuracy.

However, the Oxford English Dictionary admitted in 2011 that the common usage of literally to add emphasis had become so widespread that it was forced to alter its definition slightly.

2.

What you think: They mean the same thing.

What they actually mean: To infer is to form an opinion based on evidence and reasoning. The listener infers. To imply is to express something in an indirect way without saying it plainly. The speaker implies.

3.

What people think it means: Rarely.

What it actually means: At infrequent or irregular intervals.

4.

What you think they mean: The same thing.

What they actually mean: To reign is to hold royal office. The Queen reigns over the United Kingdom. Reins are things you use to walk a dog or harness a horse (hence the phrase “free rein”, which means to hold a horse’s reins loosely).

5.

What you think it means: Sometimes; something that happens now and then.

What it actually means: Something that recurs at fixed times, especially with the same space between individual instances.

6.

What you think it means: A fun fact of little consequence.

What it actually means: A fun fact that is not true.

7.

What you think it means: The centre of something.

What it actually means: The point on the earth’s surface directly above the focus of an earthquake.

8.

What you think it means: When something doesn’t happen very often.

What it actually means: Something that’s unchanging and constant, e.g., “The football season invariably starts in August.”

9.

What you think it means: Very quick growth.

What it actually means: An increase in the rate of growth. Something is growing exponentially when its rate of change can be described using an exponent, such as 103.

10.

What you think it means: Something that’s very big.

What it actually means: The extreme scale, seriousness, or extent of something that’s bad or morally wrong. Can also mean a grave crime or sin. As in: “We only just discovered the enormity of the crimes he committed.”

11.

What you think they mean: The same thing.

What they actually mean: The palate is the roof of the mouth and also a person’s ability to discern different flavours, while a palette is what an artist uses to mix paints.

Neither are to be confused with pallet, which is a wooden platform used to stack things.

12.

What you think it means: To deny something.

What it actually means: To prove a statement or theory to be untrue.

13.

What you think it means: To get an electric shock.

What it actually means: To injure or kill by electric shock.

14.

What you think they mean: The same thing.

What they actually mean: To flounder is to be clumsy and indecisive, flopping around like a fish out of water; to founder is to fill up with water and sink, or figuratively, to fail.

15.
What Alanis Morissette thinks it means: Anything mildly humorous.

What it actually means: Something that happens contrary to what is typically expected or appropriate. Can apply to language, as when someone sarcastically says something but means the opposite, such as: “Justin Bieber’s pants look great.”


Source – http://www.buzzfeed.com/patricksmith/words-that-dont-mean-what-you-think-they-mean#.vqoZmzdAm