What do you mean by risk aversion?

What do you mean by risk aversion? 

Ans. In simple terminology, an investor is said to be risk averse when he does not like to take risk. He expects enough risk premiums to get ready to take any risk. There are three types of investors in the market. Those who dislike risk; and try to avoid it as far as possible come under the category of risk averse. Those who are neutral about risk that means for them risk has neither utility nor disutility are risk neutral and those for whom risk has utility and they love to take risks are called risk lovers. Technically speaking, risk aversion means that an investor will not participate in a fair gamble because the disutility of loss is higher to him than the utility of gain. Those utility functions which exhibit risk aversion have negative second derivative. It means that their investment in risky assets curves with reference to wealth will be upward sloping but concave to the origin.