Disability means unable to do something. One is being called disable when he or she does not have all it takes to support life. Examples are the blind, this is because those who are blind do not possess the visual capabilities to differentiate between objects, note color, and do some work too.
The lame is disable because they do not have the ability to move from place to place and provide food for themselves. So this category of people is qualified to be called disable, that means they are not able to walk.
The deaf are not really disabled, because they could see, only that they cannot hear, so this set of people can use visual representation to communicate. Also, the numb are not so disabled, because they can do all other things but could not speak, they can also use signs to communicate.
The above listed are category of disabilities. But, in most cases, especially in Nigeria, we see adults and children who are healthy on the streets begging to eat. The question now is, who are the really disable people? Because, this set of people are capable of working, but they sit and even collect from those who are really disabled.