Well for me it means having a basic knowledge of anything. 

Common sense is actually uncommon sense.

I think common sense means finding solution smartly thinking smartly for ur problems..

Common sense is a Sound Judgment derived from experience rather than Study.  If a  child falls down while trying to learn Walking, we do not chide the child. Because, as I said above, the child did not have common sense derived from experience.

Where as if a well grown up boy or Girl falls down, he or she will be scolded for lack of Common sense. Because a certain amount of common sense is expected from a grown up boy or  Girl.

For me common sense is the ability to respond to situations spontaneously based on previous experience of self or others. It also means staying calm in the face of adversity. This may be asking too much, but probably that is the reason why we say common sense is very uncommon. 

Good morning and happy weekend to all.

@ rambabu, the example you have given lacks common sense because a child falling while learning to walk is a natural process and it gains experience through each fall. In the same manner why should a grown up boy or girl be penalized if hey fall? Common sense demands that you look for a reason as to why they fell

It is said common sense has become very uncommon these days. common sense is nothing but skill or knowledge that any one has without any specialized education. There are many day to day situations when you need decide things. Most of these an average intelligent person can solve without any specialized training. This is common sense.  

I am reminded of an incident that happened recently..while reaching school we need to pass through a narrow lane thanks to the minority politics of our local leader, and since it is just 5 feet wide when a two wheeler passes those walking need to move to the side and make way. The other day a huge Boulder had landed there from a nearby compound wall making it even more congested. For two days everybody including the staff just managed to move over it and around it but did not once think of moving the stone until a few high school boys got rid of it. So the youngsters had better common sense.

The following quote best explains what common sense is

Common sense is not a gift, its a punishment because you have to deal with everyone who doesn't have it!

Kalyani Nandurkar wrote:

The following quote best explains what common sense is

Common sense is not a gift, its a punishment because you have to deal with everyone who doesn't have it!

At times it is the simple uneducated people who come up with the most sensible suggestions to a problem... I have seen this happen scores of time !