In the realm of investments, the generally accepted opposite of risk adverse is risk taker or risk lover. A risk taker is an individual willing to a greater risk in investing in hopes of obtaining a higher, albeit less likely, return on that investment.
An aspect of determining what type of investment is most suitable to an individual is an analysis of that individual's inherent risk tolerance. The more tolerant a person is of risk, a riskier but potentially more profitable investment is more appropriate. On the other hand, a risk adverse person typically is placed in more conservative investments that are more secure but less profitable.