Definition of risk:
a source of danger; a possibility of incurring loss or misfortune; "drinking alcohol is a health hazard"
a venture undertaken without regard to possible loss or injury; "he saw the rewards but not the risks of crime"; "there was a danger he would do the wrong thing"
the probability of becoming infected given that exposure to an infectious agent has occurred
the probability of being exposed to an infectious agent
expose to a chance of loss or damage; "We risked losing a lot of money in this venture"; "Why risk your life?"; "She laid her job on the line when she told the boss that he was wrong"
take a risk in the hope of a favorable outcome; "When you buy these stocks you are gambling"